Can now get channels!

- Inject LoggerInterface across WebhookController, TalkService, and ImageCleanup
- Replace TalkService.getAvailableTalkRooms() OCS API calls with direct database queries
- Add getBaseUrl() helper to resolve localhost/SSRF constraints for internal API calls
- Update buildRichObject() to generate public link shares for file attachments
- Add saveBotPassword, debug, and debugTables endpoints to WebhookController
- Separate frontend assets (JS/CSS) from adminSettings template
- Add composer.json and autoload files for PSR-4 autoloading
- Update Admin settings to use TemplateResponse and register app icons

composer/autoload_psr4.php

@@ -0,0 +1,10 @@
+<?php
+
+// autoload_psr4.php - generated manually for Nextcloud PSR-4 autoloading
+
+$vendorDir = '';
+$baseDir = dirname(__DIR__);
+
+return [
+    'OCA\\NCdiscordhook\\' => [$baseDir . '/lib'],
+];