feat(db): Postgres schema, migrations and defects repository (T3)

Drizzle schema for projects, defects, push_subscriptions (C8); generated
migration; a defects repository (createDefect / listRecentDefects); a
programmatic migrator; and a db:verify script. section_id is a plain string
referencing in-code board ids, no FK (ADR 0001). Verified against real
Postgres: migration applies, a defect round-trips, /api/health reports db up.

server/db/repositories/defects.ts

@@ -0,0 +1,24 @@
+import { desc } from 'drizzle-orm'
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres'
+import type * as schema from '../schema'
+import { defects } from '../schema'
+
+type Db = NodePgDatabase<typeof schema>
+
+export interface NewDefect {
+  sectionId: string
+  projectId: string
+  verbatim: string
+  reporterEmail: string
+}
+
+/** Persist a filed defect and return the stored row. */
+export async function createDefect(db: Db, input: NewDefect) {
+  const [row] = await db.insert(defects).values(input).returning()
+  return row
+}
+
+/** Recent defects, newest first — the dashboard feed (F5/F6). */
+export async function listRecentDefects(db: Db, limit = 100) {
+  return db.select().from(defects).orderBy(desc(defects.createdAt)).limit(limit)
+}