Add categories and suppliers with CRUD routes

- category table with hierarchical parent_id, sort ordering, soft-delete
- supplier table with contact info, account number, payment terms
- CRUD routes for both with search on suppliers
- Zod validation schemas in @forte/shared
- Products will link to suppliers via join table (many-to-many)
- 26 tests passing

packages/backend/src/plugins/database.ts

@@ -4,8 +4,9 @@ import postgres from 'postgres'
 import * as storeSchema from '../db/schema/stores.js'
 import * as userSchema from '../db/schema/users.js'
 import * as accountSchema from '../db/schema/accounts.js'
+import * as inventorySchema from '../db/schema/inventory.js'
 
-const schema = { ...storeSchema, ...userSchema, ...accountSchema }
+const schema = { ...storeSchema, ...userSchema, ...accountSchema, ...inventorySchema }
 
 declare module 'fastify' {
   interface FastifyInstance {