feat: sentry-laravel install + scrubber + ignored exceptions

WS-7 PR-2 commit 1. Wires sentry-laravel into the app behind a
config-only no-op when SENTRY_DSN_BACKEND is empty (RFC §3.3).

- composer require sentry/sentry-laravel ^4.15 (resolved 4.25.1)
- config/sentry.php: DSN env mapped to SENTRY_DSN_BACKEND, environment
  falls back to APP_ENV, traces/profiles forced to 0.0 (RFC §2
  amendment B), send_default_pii hard-pinned false, before_send to
  SentryEventScrubber, ignore_exceptions covers ValidationException /
  AuthenticationException / AuthorizationException.
- app/Services/Observability/SentryEventScrubber.php: recursive body /
  header / query-string scrubber + form_values wholesale replacement +
  HttpException sub-500 drop (status filter that ignore_exceptions
  cannot do class-only). Max-depth guard against malicious payloads.
- app/Enums/Observability/ActorType.php: enum + resolver for §3.6
  actor_type tag (consumed by BindSentryContext in commit 2).
- tests/Feature/Observability/PiiScrubbingTest.php: 20 cases.
- api/.env.example: SENTRY_DSN_BACKEND + SENTRY_RELEASE entries.

Larastan: clean. Test count: 1487 to 1507.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/app/Enums/Observability/ActorType.php

@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Enums\Observability;
+
+use App\Models\User;
+use Illuminate\Contracts\Auth\Authenticatable;
+use Illuminate\Http\Request;
+
+/**
+ * Actor classification used as the `actor_type` Sentry tag (RFC-WS-7 §3.6).
+ *
+ * Resolution precedence (most specific first):
+ *  1. Portal-token request → PORTAL_TOKEN
+ *  2. Authenticated super_admin → SUPER_ADMIN
+ *  3. Authenticated org_admin → ORGANIZER_ADMIN
+ *  4. Authenticated volunteer (role match) → VOLUNTEER
+ *  5. Other authenticated user → ORG_MEMBER
+ *  6. None of the above → UNAUTHENTICATED
+ */
+enum ActorType: string
+{
+    case ORGANIZER_ADMIN = 'organizer_admin';
+    case SUPER_ADMIN = 'super_admin';
+    case PORTAL_TOKEN = 'portal_token';
+    case VOLUNTEER = 'volunteer';
+    case ORG_MEMBER = 'org_member';
+    case UNAUTHENTICATED = 'unauthenticated';
+
+    public static function resolve(?Authenticatable $user, ?Request $request): self
+    {
+        if ($request !== null && $request->attributes->get('portal_context') !== null) {
+            return self::PORTAL_TOKEN;
+        }
+
+        if (! $user instanceof User) {
+            return self::UNAUTHENTICATED;
+        }
+
+        if ($user->hasRole('super_admin')) {
+            return self::SUPER_ADMIN;
+        }
+
+        if ($user->hasRole('org_admin')) {
+            return self::ORGANIZER_ADMIN;
+        }
+
+        if ($user->hasRole('volunteer')) {
+            return self::VOLUNTEER;
+        }
+
+        return self::ORG_MEMBER;
+    }
+}