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.

server/db/repositories/projects.ts

@@ -0,0 +1,44 @@
+import { asc, sql } from 'drizzle-orm'
+import type { NodePgDatabase } from 'drizzle-orm/node-postgres'
+import type * as schema from '../schema'
+import { projects } from '../schema'
+
+type Db = NodePgDatabase<typeof schema>
+
+export type Project = typeof projects.$inferSelect
+
+/** The shared, global project list, alphabetical by name (F3). */
+export async function listProjects(db: Db): Promise<Project[]> {
+  return db.select().from(projects).orderBy(asc(projects.name))
+}
+
+/**
+ * Find-or-create a project by name, deduping case-insensitively so "Acme" and
+ * "acme" resolve to one project (F3). The DB enforces the same rule via a
+ * unique index on `lower(name)`; the catch handles a concurrent insert race.
+ */
+export async function createProject(db: Db, rawName: string): Promise<Project> {
+  const name = rawName.trim()
+  if (!name) throw new Error('Project name is required')
+
+  const existing = await findByName(db, name)
+  if (existing) return existing
+
+  try {
+    const [row] = await db.insert(projects).values({ name }).returning()
+    return row!
+  } catch (err) {
+    const row = await findByName(db, name)
+    if (row) return row
+    throw err
+  }
+}
+
+async function findByName(db: Db, name: string): Promise<Project | undefined> {
+  const [row] = await db
+    .select()
+    .from(projects)
+    .where(sql`lower(${projects.name}) = lower(${name})`)
+    .limit(1)
+  return row
+}