Merge website-branding feature and adjust for compatibility

- Resolved conflicts in models.py, app.py, and template files
- Added branding checks to prevent errors when g.branding is None
- Updated all template references to use conditional branding
- Added BrandingSettings to migrations
- Created branding uploads directory
- Integrated branding with existing comment and task management features

templates/system_admin_settings.html

@@ -119,7 +119,7 @@
         <div class="info-grid">
             <div class="info-card">
                 <h4>Application Version</h4>
-                <p>TimeTrack v1.0</p>
+                <p>{{ g.branding.app_name }} v1.0</p>
             </div>
             <div class="info-card">
                 <h4>Database</h4>