feat(defects): read API — feed, per-section counts and history (T6)

GET /api/defects returns a newest-first feed joined to the project name,
bounded by limit; ?section=ID narrows to one section's history. GET
/api/defects/counts returns { sectionId: n } for the weak-point map. Adds a
(section_id, created_at) index and a db:seed script; ~2k rows query in ~20ms.

server/db/repositories/defects.ts

@@ -1,7 +1,7 @@
-import { desc } from 'drizzle-orm'
+import { desc, eq, sql } from 'drizzle-orm'
 import type { NodePgDatabase } from 'drizzle-orm/node-postgres'
 import type * as schema from '../schema'
-import { defects } from '../schema'
+import { defects, projects } from '../schema'
 
 type Db = NodePgDatabase<typeof schema>
 
@@ -22,3 +22,48 @@ export async function createDefect(db: Db, input: NewDefect) {
 export async function listRecentDefects(db: Db, limit = 100) {
   return db.select().from(defects).orderBy(desc(defects.createdAt)).limit(limit)
 }
+
+export interface DefectView {
+  id: string
+  sectionId: string
+  projectId: string
+  projectName: string
+  verbatim: string
+  reporterEmail: string
+  createdAt: Date
+}
+
+/**
+ * Defects for the dashboard (F6), newest-first and joined to the project name.
+ * The whole feed by default; one section's history when `sectionId` is given
+ * (the lazy modal load). Always bounded by `limit`.
+ */
+export async function listDefects(
+  db: Db,
+  opts: { sectionId?: string; limit?: number } = {},
+): Promise<DefectView[]> {
+  return db
+    .select({
+      id: defects.id,
+      sectionId: defects.sectionId,
+      projectId: defects.projectId,
+      projectName: projects.name,
+      verbatim: defects.verbatim,
+      reporterEmail: defects.reporterEmail,
+      createdAt: defects.createdAt,
+    })
+    .from(defects)
+    .innerJoin(projects, eq(projects.id, defects.projectId))
+    .where(opts.sectionId ? eq(defects.sectionId, opts.sectionId) : undefined)
+    .orderBy(desc(defects.createdAt))
+    .limit(opts.limit ?? 100)
+}
+
+/** Per-section defect counts `{ sectionId: n }` for the weak-point map (F4/F6). */
+export async function countDefectsBySection(db: Db): Promise<Record<string, number>> {
+  const rows = await db
+    .select({ sectionId: defects.sectionId, count: sql<number>`count(*)::int` })
+    .from(defects)
+    .groupBy(defects.sectionId)
+  return Object.fromEntries(rows.map((r) => [r.sectionId, r.count]))
+}