api: pair the mobile app with device tokens

MB1 (spec 13). Decision 0005: our own Android/iPhone app, Expo in the
mobile repo, user portal only, no push in v1.

- mobile_devices (migration 0013): one-time pairing codes from My settings
  (QR or server + code, 10 minutes), traded by the app for an spm_ device
  token that acts as its user and never as an admin
- POST /api/me/mobile-devices/pair (web session only), POST /api/mobile/pair,
  GET/DELETE /api/me/mobile-devices
- signing out everywhere (password change or reset, disabling) removes
  paired phones too
- My settings: Mobile app section with the QR code and paired phones
- mobile/ (its own repo) ignored here

apps/api/test/schema.test.ts

@@ -115,11 +115,11 @@ describe.skipIf(!hasTestDb)('schema matches spec 02', () => {
   beforeAll(async () => ({ db, drop } = await createTestDb()));
   afterAll(() => drop?.());
 
-  it('creates all 44 tables', async () => {
+  it('creates all 45 tables', async () => {
     const r = await db.execute(
       sql`select count(*)::int as n from information_schema.tables where table_schema = 'public'`,
     );
-    expect(r.rows[0]).toEqual({ n: 44 });
+    expect(r.rows[0]).toEqual({ n: 45 });
   });
 
   it.each(Object.keys(EXPECTED))('%s columns', async (table) => {