feat(api): mobile API Milestone 1+2 — Sanctum auth + offline sync vertical slice

Milestone 1 (auth foundation):
- Installed laravel/sanctum; HasApiTokens on User; published config + migration.
- routes/api.php with /api/v1; Sanctum 'ability' middleware alias registered.
- AuthController: POST login (long-lived revocable device token w/ ability
  mobile-sync + devices table), GET me, POST logout. New Device model/table.

Milestone 2 (vertical slice, offline-first):
- progress_updates: +uuid (client-generated) +client_updated_at.
- ProjectApiController: GET projects (accessibleBy), GET projects/{id}/bundle
  (project/phases/layers/features, membership-authorized).
- SyncController: POST sync — batch ops, idempotent by uuid, per-op result
  (applied/duplicate/error), server-set user_id, authz by permission+membership.
  Currently handles progress_update.create.

Tests: tests/Feature/Api/MobileApiTest (9 passing) — auth, accessible projects,
bundle authz, sync apply+idempotency, permission enforcement.

Also fixed a latent schema bug: projects.reference (and external_reference_1)
existed in the live DB but had no migration — added a guarded migration so fresh
installs match production.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

composer.json

@@ -10,6 +10,7 @@
         "blade-ui-kit/blade-heroicons": "^2.7",
         "gasparesganga/php-shapefile": "^3.4",
         "laravel/framework": "^12.0",
+        "laravel/sanctum": "^4.3",
         "laravel/tinker": "^2.10.1",
         "league/geotools": "^1.3",
         "livewire/livewire": "^3.6.4",