Integrate branding and theme settings with database

- Update BrandingPage to save settings to database instead of localStorage
- Add public settings endpoint for galleries to fetch branding/theme
- Update GalleryView to apply branding settings in footer
- Apply theme settings from database to gallery pages
- Support event-specific themes that override global settings
- Ensure watermark and all branding settings are stored in database

backend/src/routes/publicSettings.js

@@ -0,0 +1,43 @@
+const express = require('express');
+const { db } = require('../database/db');
+const router = express.Router();
+
+// Get public settings (branding and theme)
+router.get('/', async (req, res) => {
+  try {
+    // Fetch branding and theme settings
+    const settings = await db('app_settings')
+      .whereIn('setting_type', ['branding', 'theme'])
+      .select('setting_key', 'setting_value');
+    
+    // Convert to object format
+    const settingsObject = {};
+    settings.forEach(setting => {
+      try {
+        settingsObject[setting.setting_key] = setting.setting_value 
+          ? JSON.parse(setting.setting_value) 
+          : null;
+      } catch (e) {
+        // If parsing fails, use the raw value
+        settingsObject[setting.setting_key] = setting.setting_value;
+      }
+    });
+
+    // Return only safe public settings
+    const publicSettings = {
+      branding_company_name: settingsObject.branding_company_name || '',
+      branding_company_tagline: settingsObject.branding_company_tagline || '',
+      branding_support_email: settingsObject.branding_support_email || '',
+      branding_footer_text: settingsObject.branding_footer_text || '',
+      branding_watermark_enabled: settingsObject.branding_watermark_enabled || false,
+      theme_config: settingsObject.theme_config || null
+    };
+
+    res.json(publicSettings);
+  } catch (error) {
+    console.error('Public settings fetch error:', error);
+    res.status(500).json({ error: 'Failed to fetch settings' });
+  }
+});
+
+module.exports = router;