feat(projects): list + create API and creatable ProjectAutocomplete (T4)

- GET /api/projects returns the shared global list; POST /api/projects
  creates a project, deduped case-insensitively (F3).
- Repository find-or-create trims and matches on lower(name); a unique index
  on lower(name) enforces the same rule at the DB (replacing the case-
  sensitive column unique constraint) — migration 0001.
- ProjectAutocomplete: creatable autocomplete that lists projects, offers to
  create an unknown name inline, and selects it without reload.
- Integration test (dedupe/list against Postgres) + component test.

tests/projects.spec.ts

@@ -0,0 +1,70 @@
+import { describe, it, expect, beforeAll, beforeEach, afterAll } from 'vitest'
+import { setupTestDb, truncateAll, type TestDb } from './helpers/db'
+import { createProject, listProjects } from '../server/db/repositories/projects'
+
+let db: TestDb
+let pool: { end: () => Promise<void> }
+
+beforeAll(async () => {
+  const setup = await setupTestDb()
+  db = setup.db
+  pool = setup.pool
+})
+
+afterAll(async () => {
+  await pool.end()
+})
+
+beforeEach(async () => {
+  await truncateAll(db)
+})
+
+describe('projects repository', () => {
+  it('lists nothing when no projects exist', async () => {
+    expect(await listProjects(db)).toEqual([])
+  })
+
+  it('creates a project and lists it', async () => {
+    const created = await createProject(db, 'Acme')
+    expect(created.id).toBeDefined()
+    expect(created.name).toBe('Acme')
+
+    const list = await listProjects(db)
+    expect(list).toHaveLength(1)
+    expect(list[0]!.name).toBe('Acme')
+  })
+
+  it('dedupes case-insensitively — "Acme" then "acme" yields one project', async () => {
+    const first = await createProject(db, 'Acme')
+    const second = await createProject(db, 'acme')
+
+    expect(second.id).toBe(first.id)
+    expect(second.name).toBe('Acme') // keeps the original casing
+    expect(await listProjects(db)).toHaveLength(1)
+  })
+
+  it('trims surrounding whitespace and dedupes against the trimmed name', async () => {
+    const first = await createProject(db, 'Globex')
+    const second = await createProject(db, '  globex  ')
+
+    expect(second.id).toBe(first.id)
+    expect(await listProjects(db)).toHaveLength(1)
+  })
+
+  it('rejects a blank name', async () => {
+    await expect(createProject(db, '   ')).rejects.toThrow()
+    expect(await listProjects(db)).toHaveLength(0)
+  })
+
+  it('lists projects alphabetically by name', async () => {
+    await createProject(db, 'Zebra')
+    await createProject(db, 'Acme')
+    await createProject(db, 'Monarch')
+
+    expect((await listProjects(db)).map((p) => p.name)).toEqual([
+      'Acme',
+      'Monarch',
+      'Zebra',
+    ])
+  })
+})