Add repair notes journal with running feed, visibility, and status tagging

New repair_note table for timestamped journal entries on tickets. Each
note captures author, content, visibility (internal or customer-facing),
and the ticket status at time of writing. Notes display as a running
feed on the ticket detail page with newest first. Internal notes have
a lock icon, customer-visible notes highlighted in blue. Supports add
and delete with appropriate permission gating.

packages/backend/src/db/migrations/0018_repair_notes.sql

@@ -0,0 +1,12 @@
+CREATE TYPE "repair_note_visibility" AS ENUM ('internal', 'customer');
+
+CREATE TABLE "repair_note" (
+  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+  "repair_ticket_id" uuid NOT NULL REFERENCES "repair_ticket"("id"),
+  "author_id" uuid NOT NULL REFERENCES "user"("id"),
+  "author_name" varchar(255) NOT NULL,
+  "content" text NOT NULL,
+  "visibility" "repair_note_visibility" NOT NULL DEFAULT 'internal',
+  "ticket_status" "repair_ticket_status",
+  "created_at" timestamp with time zone NOT NULL DEFAULT now()
+);

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

@@ -127,6 +127,13 @@
       "when": 1774770000000,
       "tag": "0017_repair_in_transit_status",
       "breakpoints": true
+    },
+    {
+      "idx": 18,
+      "version": "7",
+      "when": 1774780000000,
+      "tag": "0018_repair_notes",
+      "breakpoints": true
     }
   ]
 }

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

@@ -140,6 +140,26 @@ export const repairLineItems = pgTable('repair_line_item', {
   createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
 })
 
+export const repairNoteVisibilityEnum = pgEnum('repair_note_visibility', ['internal', 'customer'])
+
+export const repairNotes = pgTable('repair_note', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  repairTicketId: uuid('repair_ticket_id')
+    .notNull()
+    .references(() => repairTickets.id),
+  authorId: uuid('author_id')
+    .notNull()
+    .references(() => users.id),
+  authorName: varchar('author_name', { length: 255 }).notNull(),
+  content: text('content').notNull(),
+  visibility: repairNoteVisibilityEnum('visibility').notNull().default('internal'),
+  ticketStatus: repairTicketStatusEnum('ticket_status'),
+  createdAt: timestamp('created_at', { withTimezone: true }).notNull().defaultNow(),
+})
+
+export type RepairNote = typeof repairNotes.$inferSelect
+export type RepairNoteInsert = typeof repairNotes.$inferInsert
+
 export const repairServiceTemplates = pgTable('repair_service_template', {
   id: uuid('id').primaryKey().defaultRandom(),
   companyId: uuid('company_id')