feat(121+122): smsplanet conversation, notifications, default footer

Phase 121 — SMSPLANET Conversation + Notifications:
- migration 20260512_000110 adds smsplanet conversation + notifications tables
- src/Modules/Sms (SmsConversationService, SmsMessageRepository, SmsplanetWebhookController)
- src/Modules/Notifications (Repository, Controller, ApiController)
- order SMS tab, notification center, sender mode, inbound webhook
- public notifications.js + layouts/app.php integration

Phase 122 — SMSPLANET Default SMS Footer:
- migration 20260512_000111 adds smsplanet_integration_settings.default_footer
- footer appended to test SMS and order SMS, validated against 918 char limit
- settings textarea + compact order SMS note when footer configured

Bundled (could not split per-phase without hunk staging):
- routes/web.php (also carries Phase 118 fakturownia redirects)
- DOCS/{ARCHITECTURE,DB_SCHEMA,TECH_CHANGELOG}.md (118 + 121 + 122 entries)
- .paul/codebase/{architecture,db_schema,tech_changelog}.md (118 + 121 + 122)
- .paul/STATE.md, ROADMAP.md, changelog/2026-05-12.md (UNIFY closure)

Co-Authored-By: Claude <noreply@anthropic.com>

src/Modules/Notifications/NotificationApiController.php

@@ -0,0 +1,40 @@
+<?php
+declare(strict_types=1);
+
+namespace App\Modules\Notifications;
+
+use App\Core\Http\Request;
+use App\Core\Http\Response;
+
+final class NotificationApiController
+{
+    public function __construct(private readonly NotificationRepository $repository)
+    {
+    }
+
+    public function unread(Request $request): Response
+    {
+        return Response::json([
+            'ok' => true,
+            'count' => $this->repository->unreadCount(),
+            'items' => array_map(
+                static fn (array $row): array => [
+                    'id' => (int) ($row['id'] ?? 0),
+                    'type' => (string) ($row['type'] ?? ''),
+                    'title' => (string) ($row['title'] ?? ''),
+                    'body' => (string) ($row['body'] ?? ''),
+                    'target_url' => (string) ($row['target_url'] ?? ''),
+                    'created_at' => (string) ($row['created_at'] ?? ''),
+                ],
+                $this->repository->recentUnread(10)
+            ),
+        ]);
+    }
+
+    public function markRead(Request $request): Response
+    {
+        $this->repository->markRead(max(0, (int) $request->input('id', 0)));
+
+        return Response::json(['ok' => true, 'count' => $this->repository->unreadCount()]);
+    }
+}