Implement file storage layer with local provider, upload/download API, tests

- StorageProvider interface with LocalProvider (S3 placeholder)
- File table with entity_type/entity_id references, content type, path
- POST /v1/files (multipart upload), GET /v1/files (list by entity),
  GET /v1/files/:id (metadata), GET /v1/files/serve/* (content),
  DELETE /v1/files/:id
- member_identifier drops base64 columns, uses file_id FKs
- File validation: type whitelist, size limits, per-entity max
- Fastify storage plugin injects provider into app
- 6 API tests for upload, list, get, delete, validation
- Test runner kills stale port before starting backend

packages/backend/api-tests/lib/context.ts

@@ -3,6 +3,8 @@ import { type TestResult, printSuiteHeader, printTestResult } from './reporter.j
 
 export interface TestContext {
   api: ApiClient
+  token: string
+  baseUrl: string
   test: (name: string, optsOrFn: { tags?: string[] } | (() => Promise<void>), maybeFn?: () => Promise<void>) => void
   assert: {
     status: (res: ApiResponse, expected: number) => void
@@ -117,6 +119,8 @@ export async function runSuite(
 
   const ctx: TestContext = {
     api,
+    token,
+    baseUrl,
     assert: makeAssert(),
     test(name, optsOrFn, maybeFn) {
       const opts = typeof optsOrFn === 'function' ? {} : optsOrFn

packages/backend/api-tests/run.ts

@@ -77,7 +77,16 @@ async function setupDatabase() {
 }
 
 // --- Start backend ---
+async function killPort(port: number) {
+  try {
+    const { execSync } = await import('child_process')
+    execSync(`lsof -ti:${port} | xargs kill -9 2>/dev/null || true`, { stdio: 'pipe' })
+    await new Promise((r) => setTimeout(r, 1000))
+  } catch {}
+}
+
 async function startBackend(): Promise<Subprocess> {
+  await killPort(TEST_PORT)
   const proc = spawn({
     cmd: ['bun', 'run', 'src/main.ts'],
     cwd: new URL('..', import.meta.url).pathname,
@@ -90,6 +99,7 @@ async function startBackend(): Promise<Subprocess> {
       HOST: '0.0.0.0',
       NODE_ENV: 'development',
       LOG_LEVEL: 'error',
+      STORAGE_LOCAL_PATH: '/tmp/forte-test-files',
     },
     stdout: 'pipe',
     stderr: 'pipe',

packages/backend/api-tests/suites/files.ts

@@ -0,0 +1,146 @@
+import { suite } from '../lib/context.js'
+
+// Helper: create a tiny 1x1 JPEG for testing uploads
+const TINY_JPEG = Buffer.from(
+  '/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEB' +
+  'AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/2wBDAQEBAQEBAQEBAQEBAQEBAQEBAQEB' +
+  'AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQH/wAARCAABAAEDASIA' +
+  'AhEBAxEB/8QAFAABAAAAAAAAAAAAAAAAAAAACf/EABQQAQAAAAAAAAAAAAAAAAAAAAD/xAAUAQEA' +
+  'AAAAAAAAAAAAAAAAAAAB/8QAFBEBAAAAAAAAAAAAAAAAAAAAAP/aAAwDAQACEQMRAD8AJgA//9k=',
+  'base64',
+)
+
+suite('Files', { tags: ['files', 'storage'] }, (t) => {
+  t.test('uploads an image file', { tags: ['upload'] }, async () => {
+    const acct = await t.api.post('/v1/accounts', { name: 'File Test' })
+    const member = await t.api.post(`/v1/accounts/${acct.data.id}/members`, {
+      firstName: 'File',
+      lastName: 'Test',
+    })
+
+    // Upload via multipart
+    const formData = new FormData()
+    formData.append('file', new Blob([TINY_JPEG], { type: 'image/jpeg' }), 'test.jpg')
+    formData.append('entityType', 'member_identifier')
+    formData.append('entityId', member.data.id)
+    formData.append('category', 'front')
+
+    const res = await fetch(`${t.baseUrl}/v1/files`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${t.token}` },
+      body: formData,
+    })
+    const data = await res.json()
+
+    t.assert.equal(res.status, 201)
+    t.assert.ok(data.id)
+    t.assert.equal(data.contentType, 'image/jpeg')
+    t.assert.equal(data.entityType, 'member_identifier')
+    t.assert.equal(data.category, 'front')
+    t.assert.ok(data.url)
+  })
+
+  t.test('lists files for an entity', { tags: ['read'] }, async () => {
+    const acct = await t.api.post('/v1/accounts', { name: 'File List Test' })
+    const member = await t.api.post(`/v1/accounts/${acct.data.id}/members`, {
+      firstName: 'List',
+      lastName: 'Files',
+    })
+
+    // Upload a file first
+    const formData = new FormData()
+    formData.append('file', new Blob([TINY_JPEG], { type: 'image/jpeg' }), 'list-test.jpg')
+    formData.append('entityType', 'member_identifier')
+    formData.append('entityId', member.data.id)
+    formData.append('category', 'back')
+
+    await fetch(`${t.baseUrl}/v1/files`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${t.token}` },
+      body: formData,
+    })
+
+    const res = await t.api.get('/v1/files', {
+      entityType: 'member_identifier',
+      entityId: member.data.id,
+    })
+    t.assert.status(res, 200)
+    t.assert.greaterThan(res.data.data.length, 0)
+    t.assert.ok(res.data.data[0].url)
+  })
+
+  t.test('gets file metadata by id', { tags: ['read'] }, async () => {
+    const acct = await t.api.post('/v1/accounts', { name: 'File Get Test' })
+    const member = await t.api.post(`/v1/accounts/${acct.data.id}/members`, {
+      firstName: 'Get',
+      lastName: 'File',
+    })
+
+    const formData = new FormData()
+    formData.append('file', new Blob([TINY_JPEG], { type: 'image/jpeg' }), 'get-test.jpg')
+    formData.append('entityType', 'member_identifier')
+    formData.append('entityId', member.data.id)
+    formData.append('category', 'front')
+
+    const uploadRes = await fetch(`${t.baseUrl}/v1/files`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${t.token}` },
+      body: formData,
+    })
+    const uploaded = await uploadRes.json()
+
+    const res = await t.api.get(`/v1/files/${uploaded.id}`)
+    t.assert.status(res, 200)
+    t.assert.equal(res.data.id, uploaded.id)
+    t.assert.equal(res.data.filename, 'get-test.jpg')
+  })
+
+  t.test('deletes a file', { tags: ['delete'] }, async () => {
+    const acct = await t.api.post('/v1/accounts', { name: 'File Delete Test' })
+    const member = await t.api.post(`/v1/accounts/${acct.data.id}/members`, {
+      firstName: 'Delete',
+      lastName: 'File',
+    })
+
+    const formData = new FormData()
+    formData.append('file', new Blob([TINY_JPEG], { type: 'image/jpeg' }), 'delete-test.jpg')
+    formData.append('entityType', 'member_identifier')
+    formData.append('entityId', member.data.id)
+    formData.append('category', 'front')
+
+    const uploadRes = await fetch(`${t.baseUrl}/v1/files`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${t.token}` },
+      body: formData,
+    })
+    const uploaded = await uploadRes.json()
+
+    const res = await t.api.del(`/v1/files/${uploaded.id}`)
+    t.assert.status(res, 200)
+
+    const check = await t.api.get(`/v1/files/${uploaded.id}`)
+    t.assert.status(check, 404)
+  })
+
+  t.test('rejects unsupported file types', { tags: ['validation'] }, async () => {
+    const acct = await t.api.post('/v1/accounts', { name: 'File Reject Test' })
+
+    const formData = new FormData()
+    formData.append('file', new Blob(['not an image'], { type: 'text/plain' }), 'test.txt')
+    formData.append('entityType', 'member_identifier')
+    formData.append('entityId', acct.data.id)
+    formData.append('category', 'front')
+
+    const res = await fetch(`${t.baseUrl}/v1/files`, {
+      method: 'POST',
+      headers: { Authorization: `Bearer ${t.token}` },
+      body: formData,
+    })
+    t.assert.equal(res.status, 400)
+  })
+
+  t.test('returns 404 for missing file', { tags: ['read'] }, async () => {
+    const res = await t.api.get('/v1/files/a0000000-0000-0000-0000-999999999999')
+    t.assert.status(res, 404)
+  })
+})

packages/backend/package.json

@@ -17,6 +17,7 @@
   "dependencies": {
     "@fastify/cors": "^10",
     "@fastify/jwt": "^9",
+    "@fastify/multipart": "^9.4.0",
     "@fastify/rate-limit": "^10.3.0",
     "@forte/shared": "workspace:*",
     "bcrypt": "^6",

packages/backend/src/db/migrations/0012_file_storage.sql

@@ -0,0 +1,25 @@
+-- File storage table
+CREATE TABLE IF NOT EXISTS "file" (
+  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+  "company_id" uuid NOT NULL REFERENCES "company"("id"),
+  "path" varchar(1000) NOT NULL,
+  "filename" varchar(255) NOT NULL,
+  "content_type" varchar(100) NOT NULL,
+  "size_bytes" integer NOT NULL,
+  "entity_type" varchar(100) NOT NULL,
+  "entity_id" uuid NOT NULL,
+  "category" varchar(100) NOT NULL,
+  "uploaded_by" uuid,
+  "created_at" timestamp with time zone NOT NULL DEFAULT now()
+);
+
+CREATE UNIQUE INDEX "file_company_path" ON "file" ("company_id", "path");
+CREATE INDEX "file_entity" ON "file" ("company_id", "entity_type", "entity_id");
+
+-- Update member_identifier: replace base64 columns with file references
+ALTER TABLE "member_identifier" DROP COLUMN IF EXISTS "image_front";
+ALTER TABLE "member_identifier" DROP COLUMN IF EXISTS "image_back";
+ALTER TABLE "member_identifier" DROP COLUMN IF EXISTS "image_front_url";
+ALTER TABLE "member_identifier" DROP COLUMN IF EXISTS "image_back_url";
+ALTER TABLE "member_identifier" ADD COLUMN "image_front_file_id" uuid REFERENCES "file"("id");
+ALTER TABLE "member_identifier" ADD COLUMN "image_back_file_id" uuid REFERENCES "file"("id");

packages/backend/src/db/migrations/meta/_journal.json

@@ -85,6 +85,13 @@
       "when": 1774710000000,
       "tag": "0011_member_address",
       "breakpoints": true
+    },
+    {
+      "idx": 12,
+      "version": "7",
+      "when": 1774720000000,
+      "tag": "0012_file_storage",
+      "breakpoints": true
     }
   ]
 }

packages/backend/src/db/schema/accounts.ts

@@ -82,8 +82,8 @@ export const memberIdentifiers = pgTable('member_identifier', {
   issuingAuthority: varchar('issuing_authority', { length: 255 }),
   issuedDate: date('issued_date'),
   expiresAt: date('expires_at'),
-  imageFront: text('image_front'),
-  imageBack: text('image_back'),
+  imageFrontFileId: uuid('image_front_file_id'),
+  imageBackFileId: uuid('image_back_file_id'),
   notes: text('notes'),
   isPrimary: boolean('is_primary').notNull().default(false),
   createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),

packages/backend/src/db/schema/files.ts

@@ -0,0 +1,21 @@
+import { pgTable, uuid, varchar, integer, timestamp } from 'drizzle-orm/pg-core'
+import { companies } from './stores.js'
+
+export const files = pgTable('file', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  companyId: uuid('company_id')
+    .notNull()
+    .references(() => companies.id),
+  path: varchar('path', { length: 1000 }).notNull(),
+  filename: varchar('filename', { length: 255 }).notNull(),
+  contentType: varchar('content_type', { length: 100 }).notNull(),
+  sizeBytes: integer('size_bytes').notNull(),
+  entityType: varchar('entity_type', { length: 100 }).notNull(),
+  entityId: uuid('entity_id').notNull(),
+  category: varchar('category', { length: 100 }).notNull(),
+  uploadedBy: uuid('uploaded_by'),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+})
+
+export type FileRecord = typeof files.$inferSelect
+export type FileRecordInsert = typeof files.$inferInsert

packages/backend/src/main.ts

@@ -6,12 +6,14 @@ import { corsPlugin } from './plugins/cors.js'
 import { errorHandlerPlugin } from './plugins/error-handler.js'
 import { authPlugin } from './plugins/auth.js'
 import { devAuthPlugin } from './plugins/dev-auth.js'
+import { storagePlugin } from './plugins/storage.js'
 import { healthRoutes } from './routes/v1/health.js'
 import { authRoutes } from './routes/v1/auth.js'
 import { accountRoutes } from './routes/v1/accounts.js'
 import { inventoryRoutes } from './routes/v1/inventory.js'
 import { productRoutes } from './routes/v1/products.js'
 import { lookupRoutes } from './routes/v1/lookups.js'
+import { fileRoutes } from './routes/v1/files.js'
 
 export async function buildApp() {
   const app = Fastify({
@@ -28,6 +30,7 @@ export async function buildApp() {
   await app.register(databasePlugin)
   await app.register(redisPlugin)
   await app.register(rateLimit, { global: false })
+  await app.register(storagePlugin)
 
   // Auth — JWT in production/test, dev bypass only in development without JWT_SECRET
   if (process.env.JWT_SECRET) {
@@ -46,6 +49,7 @@ export async function buildApp() {
   await app.register(inventoryRoutes, { prefix: '/v1' })
   await app.register(productRoutes, { prefix: '/v1' })
   await app.register(lookupRoutes, { prefix: '/v1' })
+  await app.register(fileRoutes, { prefix: '/v1' })
 
   return app
 }

packages/backend/src/plugins/storage.ts

@@ -0,0 +1,14 @@
+import fp from 'fastify-plugin'
+import { createStorageProvider, type StorageProvider } from '../storage/index.js'
+
+declare module 'fastify' {
+  interface FastifyInstance {
+    storage: StorageProvider
+  }
+}
+
+export const storagePlugin = fp(async (app) => {
+  const storage = createStorageProvider()
+  app.decorate('storage', storage)
+  app.log.info(`Storage provider: ${process.env.STORAGE_PROVIDER ?? 'local'}`)
+})

packages/backend/src/routes/v1/files.ts

@@ -0,0 +1,106 @@
+import type { FastifyPluginAsync } from 'fastify'
+import multipart from '@fastify/multipart'
+import { FileService } from '../../services/file.service.js'
+
+export const fileRoutes: FastifyPluginAsync = async (app) => {
+  await app.register(multipart, {
+    limits: {
+      fileSize: 25 * 1024 * 1024, // 25 MB max
+      files: 1,
+    },
+  })
+
+  // List files for an entity
+  app.get('/files', { preHandler: [app.authenticate] }, async (request, reply) => {
+    const { entityType, entityId } = request.query as { entityType?: string; entityId?: string }
+    if (!entityType || !entityId) {
+      return reply.status(400).send({
+        error: { message: 'entityType and entityId query params required', statusCode: 400 },
+      })
+    }
+
+    const fileRecords = await FileService.listByEntity(app.db, request.companyId, entityType, entityId)
+    const data = await Promise.all(
+      fileRecords.map(async (f) => ({ ...f, url: await app.storage.getUrl(f.path) })),
+    )
+    return reply.send({ data })
+  })
+
+  // Upload a file
+  app.post('/files', { preHandler: [app.authenticate] }, async (request, reply) => {
+    const data = await request.file()
+    if (!data) {
+      return reply.status(400).send({ error: { message: 'No file provided', statusCode: 400 } })
+    }
+
+    const entityType = (data.fields.entityType as { value?: string })?.value
+    const entityId = (data.fields.entityId as { value?: string })?.value
+    const category = (data.fields.category as { value?: string })?.value
+
+    if (!entityType || !entityId || !category) {
+      return reply.status(400).send({
+        error: { message: 'entityType, entityId, and category are required', statusCode: 400 },
+      })
+    }
+
+    const buffer = await data.toBuffer()
+
+    try {
+      const file = await FileService.upload(app.db, app.storage, request.companyId, {
+        data: buffer,
+        filename: data.filename,
+        contentType: data.mimetype,
+        entityType,
+        entityId,
+        category,
+        uploadedBy: request.user.id,
+      })
+      const url = await app.storage.getUrl(file.path)
+      return reply.status(201).send({ ...file, url })
+    } catch (err) {
+      if (err instanceof Error && (err.message.includes('not allowed') || err.message.includes('too large') || err.message.includes('Maximum'))) {
+        return reply.status(400).send({ error: { message: err.message, statusCode: 400 } })
+      }
+      throw err
+    }
+  })
+
+  // Serve file content (for local provider)
+  app.get('/files/serve/*', { preHandler: [app.authenticate] }, async (request, reply) => {
+    const filePath = (request.params as { '*': string })['*']
+    if (!filePath) {
+      return reply.status(400).send({ error: { message: 'Path required', statusCode: 400 } })
+    }
+
+    try {
+      const data = await app.storage.get(filePath)
+      const ext = filePath.split('.').pop()?.toLowerCase()
+      const contentTypeMap: Record<string, string> = {
+        jpg: 'image/jpeg', jpeg: 'image/jpeg', png: 'image/png', webp: 'image/webp', pdf: 'application/pdf',
+      }
+      return reply
+        .header('Content-Type', contentTypeMap[ext ?? ''] ?? 'application/octet-stream')
+        .header('Cache-Control', 'private, max-age=3600')
+        .send(data)
+    } catch {
+      return reply.status(404).send({ error: { message: 'File not found', statusCode: 404 } })
+    }
+  })
+
+  // Get file metadata
+  app.get('/files/:id', { preHandler: [app.authenticate] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const file = await FileService.getById(app.db, request.companyId, id)
+    if (!file) return reply.status(404).send({ error: { message: 'File not found', statusCode: 404 } })
+    const url = await app.storage.getUrl(file.path)
+    return reply.send({ ...file, url })
+  })
+
+  // Delete a file
+  app.delete('/files/:id', { preHandler: [app.authenticate] }, async (request, reply) => {
+    const { id } = request.params as { id: string }
+    const file = await FileService.delete(app.db, app.storage, request.companyId, id)
+    if (!file) return reply.status(404).send({ error: { message: 'File not found', statusCode: 404 } })
+    return reply.send(file)
+  })
+}

packages/backend/src/services/account.service.ts

@@ -607,8 +607,8 @@ export const MemberIdentifierService = {
         issuingAuthority: input.issuingAuthority,
         issuedDate: input.issuedDate,
         expiresAt: input.expiresAt,
-        imageFrontUrl: input.imageFrontUrl,
-        imageBackUrl: input.imageBackUrl,
+        imageFrontFileId: input.imageFrontFileId,
+        imageBackFileId: input.imageBackFileId,
         notes: input.notes,
         isPrimary: input.isPrimary,
       })

packages/backend/src/services/file.service.ts

@@ -0,0 +1,139 @@
+import { eq, and, count } from 'drizzle-orm'
+import type { PostgresJsDatabase } from 'drizzle-orm/postgres-js'
+import { files } from '../db/schema/files.js'
+import type { StorageProvider } from '../storage/index.js'
+import { randomUUID } from 'crypto'
+
+const ALLOWED_IMAGE_TYPES = ['image/jpeg', 'image/png', 'image/webp']
+const ALLOWED_PDF_TYPES = ['application/pdf']
+const ALLOWED_TYPES = [...ALLOWED_IMAGE_TYPES, ...ALLOWED_PDF_TYPES]
+const MAX_IMAGE_SIZE = 10 * 1024 * 1024 // 10 MB
+const MAX_PDF_SIZE = 25 * 1024 * 1024 // 25 MB
+const MAX_FILES_PER_ENTITY = 20
+
+function getExtension(contentType: string): string {
+  const map: Record<string, string> = {
+    'image/jpeg': 'jpg',
+    'image/png': 'png',
+    'image/webp': 'webp',
+    'application/pdf': 'pdf',
+  }
+  return map[contentType] ?? 'bin'
+}
+
+export const FileService = {
+  async upload(
+    db: PostgresJsDatabase,
+    storage: StorageProvider,
+    companyId: string,
+    input: {
+      data: Buffer
+      filename: string
+      contentType: string
+      entityType: string
+      entityId: string
+      category: string
+      uploadedBy?: string
+    },
+  ) {
+    // Validate content type
+    if (!ALLOWED_TYPES.includes(input.contentType)) {
+      throw new Error(`File type not allowed: ${input.contentType}`)
+    }
+
+    // Validate size
+    const maxSize = ALLOWED_IMAGE_TYPES.includes(input.contentType) ? MAX_IMAGE_SIZE : MAX_PDF_SIZE
+    if (input.data.length > maxSize) {
+      throw new Error(`File too large: ${input.data.length} bytes (max ${maxSize})`)
+    }
+
+    // Check per-entity limit
+    const [existing] = await db
+      .select({ total: count() })
+      .from(files)
+      .where(
+        and(
+          eq(files.companyId, companyId),
+          eq(files.entityType, input.entityType),
+          eq(files.entityId, input.entityId),
+        ),
+      )
+    if (existing.total >= MAX_FILES_PER_ENTITY) {
+      throw new Error(`Maximum ${MAX_FILES_PER_ENTITY} files per entity`)
+    }
+
+    // Generate path
+    const fileId = randomUUID()
+    const ext = getExtension(input.contentType)
+    const path = `${companyId}/${input.entityType}/${input.entityId}/${input.category}-${fileId}.${ext}`
+
+    // Write to storage
+    await storage.put(path, input.data, input.contentType)
+
+    // Insert record
+    const [file] = await db
+      .insert(files)
+      .values({
+        id: fileId,
+        companyId,
+        path,
+        filename: input.filename,
+        contentType: input.contentType,
+        sizeBytes: input.data.length,
+        entityType: input.entityType,
+        entityId: input.entityId,
+        category: input.category,
+        uploadedBy: input.uploadedBy,
+      })
+      .returning()
+
+    return file
+  },
+
+  async getById(db: PostgresJsDatabase, companyId: string, id: string) {
+    const [file] = await db
+      .select()
+      .from(files)
+      .where(and(eq(files.id, id), eq(files.companyId, companyId)))
+      .limit(1)
+    return file ?? null
+  },
+
+  async listByEntity(
+    db: PostgresJsDatabase,
+    companyId: string,
+    entityType: string,
+    entityId: string,
+  ) {
+    return db
+      .select()
+      .from(files)
+      .where(
+        and(
+          eq(files.companyId, companyId),
+          eq(files.entityType, entityType),
+          eq(files.entityId, entityId),
+        ),
+      )
+      .orderBy(files.createdAt)
+  },
+
+  async delete(
+    db: PostgresJsDatabase,
+    storage: StorageProvider,
+    companyId: string,
+    id: string,
+  ) {
+    const file = await this.getById(db, companyId, id)
+    if (!file) return null
+
+    await storage.delete(file.path)
+
+    const [deleted] = await db
+      .delete(files)
+      .where(and(eq(files.id, id), eq(files.companyId, companyId)))
+      .returning()
+
+    return deleted ?? null
+  },
+}

packages/backend/src/storage/index.ts

@@ -0,0 +1,23 @@
+import { LocalStorageProvider } from './local.js'
+import type { StorageProvider } from './provider.js'
+
+export type { StorageProvider }
+
+export function createStorageProvider(): StorageProvider {
+  const provider = process.env.STORAGE_PROVIDER ?? 'local'
+
+  if (provider === 'local') {
+    const root = process.env.STORAGE_LOCAL_PATH ?? './data/files'
+    const baseUrl = `http://localhost:${process.env.PORT ?? '8000'}`
+    return new LocalStorageProvider(root, baseUrl)
+  }
+
+  if (provider === 's3') {
+    // Lazy import to avoid requiring @aws-sdk when using local
+    throw new Error(
+      'S3 provider requires @aws-sdk/client-s3. Install it and update this factory.',
+    )
+  }
+
+  throw new Error(`Unknown storage provider: ${provider}`)
+}

packages/backend/src/storage/local.ts

@@ -0,0 +1,48 @@
+import { mkdir, readFile, writeFile, unlink, access } from 'fs/promises'
+import { dirname, join } from 'path'
+import type { StorageProvider } from './provider.js'
+
+export class LocalStorageProvider implements StorageProvider {
+  private root: string
+  private baseUrl: string
+
+  constructor(root: string, baseUrl: string) {
+    this.root = root
+    this.baseUrl = baseUrl
+  }
+
+  private fullPath(path: string): string {
+    return join(this.root, path)
+  }
+
+  async put(path: string, data: Buffer, _contentType: string): Promise<void> {
+    const fullPath = this.fullPath(path)
+    await mkdir(dirname(fullPath), { recursive: true })
+    await writeFile(fullPath, data)
+  }
+
+  async get(path: string): Promise<Buffer> {
+    return readFile(this.fullPath(path))
+  }
+
+  async delete(path: string): Promise<void> {
+    try {
+      await unlink(this.fullPath(path))
+    } catch (err: unknown) {
+      if ((err as NodeJS.ErrnoException).code !== 'ENOENT') throw err
+    }
+  }
+
+  async exists(path: string): Promise<boolean> {
+    try {
+      await access(this.fullPath(path))
+      return true
+    } catch {
+      return false
+    }
+  }
+
+  async getUrl(path: string, _expiresIn?: number): Promise<string> {
+    return `${this.baseUrl}/v1/files/serve/${encodeURIComponent(path)}`
+  }
+}

packages/backend/src/storage/provider.ts

@@ -0,0 +1,7 @@
+export interface StorageProvider {
+  put(path: string, data: Buffer, contentType: string): Promise<void>
+  get(path: string): Promise<Buffer>
+  delete(path: string): Promise<void>
+  exists(path: string): Promise<boolean>
+  getUrl(path: string, expiresIn?: number): Promise<string>
+}

packages/backend/src/storage/s3.ts

@@ -0,0 +1,47 @@
+import type { StorageProvider } from './provider.js'
+
+// S3 provider — requires @aws-sdk/client-s3 (install when needed)
+// This is a placeholder that documents the interface. Install the SDK
+// and uncomment when deploying with S3.
+
+export class S3StorageProvider implements StorageProvider {
+  private bucket: string
+  private region: string
+  private endpoint?: string
+
+  constructor(config: {
+    bucket: string
+    region: string
+    endpoint?: string
+    accessKey: string
+    secretKey: string
+  }) {
+    this.bucket = config.bucket
+    this.region = config.region
+    this.endpoint = config.endpoint
+    // TODO: initialize S3Client from @aws-sdk/client-s3
+    throw new Error(
+      'S3 provider not yet implemented. Install @aws-sdk/client-s3 and implement.',
+    )
+  }
+
+  async put(_path: string, _data: Buffer, _contentType: string): Promise<void> {
+    throw new Error('Not implemented')
+  }
+
+  async get(_path: string): Promise<Buffer> {
+    throw new Error('Not implemented')
+  }
+
+  async delete(_path: string): Promise<void> {
+    throw new Error('Not implemented')
+  }
+
+  async exists(_path: string): Promise<boolean> {
+    throw new Error('Not implemented')
+  }
+
+  async getUrl(_path: string, _expiresIn?: number): Promise<string> {
+    throw new Error('Not implemented')
+  }
+}