feat(astrolabe): add webhook management UI to admin settings

Add admin interface for configuring real-time webhook sync with
pre-configured presets for common scenarios.

Changes:
- Add webhook presets section to admin settings page
  - Shows available presets filtered by installed apps
  - Enable/disable presets with one click
  - Displays current webhook status
- Add client secret configuration status display
  - Shows whether confidential client is configured
  - Provides setup instructions for optional client secret
- Add adminSettings.js for webhook management
  - Load webhook presets via API
  - Enable/disable webhook presets
  - Handle search settings form submission
- Update vite.config.js to build adminSettings entry point
- Pass clientSecretConfigured flag to template

UI Features:
- Real-time preset status (enabled/disabled)
- One-click enable/disable for webhook bundles
- App-aware filtering (only shows presets for installed apps)
- Clear instructions for requirements and setup

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

third_party/astroglobe/lib/Settings/Admin.php

@@ -54,6 +54,8 @@ class Admin implements ISettings {
 		// Get configuration from config.php
 		$serverUrl = $this->config->getSystemValue('mcp_server_url', '');
 		$apiKeyConfigured = !empty($this->config->getSystemValue('mcp_server_api_key', ''));
+		$clientSecret = $this->config->getSystemValue('astroglobe_client_secret', '');
+		$clientSecretConfigured = !empty($clientSecret);
 
 		// Check for server connection error
 		if (isset($serverStatus['error'])) {
@@ -110,6 +112,7 @@ class Admin implements ISettings {
 			'vectorSyncStatus' => $vectorSyncStatus,
 			'serverUrl' => $serverUrl,
 			'apiKeyConfigured' => $apiKeyConfigured,
+			'clientSecretConfigured' => $clientSecretConfigured,
 			'vectorSyncEnabled' => $serverStatus['vector_sync_enabled'] ?? false,
 			'searchSettings' => $searchSettings,
 		];