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>

database/migrations/2026_06_18_070000_create_devices_table.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('devices', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('user_id')->constrained()->cascadeOnDelete();
+            $table->string('name');                       // device_name del login
+            $table->unsignedBigInteger('token_id')->nullable(); // id del personal_access_token actual
+            $table->string('app_version')->nullable();
+            $table->timestamp('last_seen_at')->nullable();
+            $table->timestamps();
+
+            $table->unique(['user_id', 'name']);
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('devices');
+    }
+};