feat: Phase 1 - Redis config, Dashboard cache, Report cache, N+1 fixes, observers

- Add predis/predis for Redis support
- Configure cache/queue defaults to redis in config + .env.example
- Create DashboardController with 60s cache for dashboard queries
- Add cache (5min) to ReportController::generate() and preview()
- Add FeatureObserver, InspectionObserver, IssueObserver for cache invalidation
- Fix N+1 in ProjectMap (eager load template, images), TaskManager (subtasks.parentTask)
- Register observers in AppServiceProvider

Tests: 101 passing (319 assertions)

app/Providers/AppServiceProvider.php

@@ -2,8 +2,14 @@
 
 namespace App\Providers;
 
+use App\Models\Feature;
+use App\Models\Inspection;
+use App\Models\Issue;
 use App\Models\Project;
 use App\Models\Task;
+use App\Observers\FeatureObserver;
+use App\Observers\InspectionObserver;
+use App\Observers\IssueObserver;
 use App\Policies\TaskPolicy;
 use Illuminate\Support\Facades\Gate;
 use Illuminate\Support\Facades\Route;
@@ -25,6 +31,11 @@ class AppServiceProvider extends ServiceProvider
      */
     public function boot(): void
     {
+        // Register model observers for cache invalidation
+        Feature::observe(FeatureObserver::class);
+        Inspection::observe(InspectionObserver::class);
+        Issue::observe(IssueObserver::class);
+
         // Re-register model bindings so they persist in route cache
         Route::model('project', Project::class);