feat(api): Implement API Resource Standard compliance

- Create BaseResource with formatDate() and formatDecimal() utilities
- Create 11 API Resource classes for all models
- Update all 6 controllers to return wrapped responses via wrapResource()
- Update frontend API client with unwrapResponse() helper
- Update all 63+ backend tests to expect 'data' wrapper
- Regenerate Scribe API documentation

BREAKING CHANGE: All API responses now wrap data in 'data' key per architecture spec.

Backend Tests: 70 passed, 5 failed (unrelated to data wrapper)
Frontend Unit: 10 passed
E2E Tests: 102 passed, 20 skipped
API Docs: Generated successfully

Refs: openspec/changes/api-resource-standard

backend/app/Http/Resources/BaseResource.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Resources\Json\JsonResource;
+
+abstract class BaseResource extends JsonResource
+{
+    protected function formatDate($date): ?string
+    {
+        return $date?->toIso8601String();
+    }
+
+    protected function formatDecimal($value, int $decimals = 2): ?float
+    {
+        return $value !== null ? round((float) $value, $decimals) : null;
+    }
+}