feature: integrate Donorbox API for donation management

- Add Donorbox configuration in site/config/config.php with API settings
- Create controller for support page to fetch campaign data from API
- Update support.php template with dynamic donation buttons and gauge
- Transform static buttons into dynamic links with proper URL parameters
- Add JavaScript for tab switching between one-time and monthly donations
- Calculate donation percentage and display real-time campaign stats

The donation buttons now link directly to Donorbox with pre-filled amounts
and intervals. API integration is ready but requires API key configuration.

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

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

site/config/config.php

@@ -24,5 +24,11 @@ return [
   ],
   'panel' => [
     'menu' => require_once __DIR__ . '/menu.php'
+  ],
+  'donorbox' => [
+    'api_key' => '', // À remplir avec la clé API Donorbox
+    'campaign_slug' => 'soutenir-index-en-2024',
+    'campaign_url' => 'https://donorbox.org/soutenir-index-en-2024',
+    'api_base_url' => 'https://donorbox.org/api/v1'
   ]
 ];