Implement editing users management and permission updates

- Added auto-creation of PlayerUser records from player metadata (user_card_data)
- Fixed player_user table schema (removed player_id, made user_code unique globally)
- Created admin page for managing editing users (view, update names, delete)
- Updated permissions: normal users can now access admin panel, editing users, and leftover media
- Admin-only access: user management, system dependencies, logo customization
- Fixed edited media workflow to preserve original files
- Content.filename now points to edited_media folder, keeping originals intact
- Added user display names in edited media page (shows name if set, code otherwise)
- Fixed leftover media file size calculation (handle None values)
- Split editing users into separate card on admin panel with description

app/templates/players/edited_media.html

@@ -376,7 +376,7 @@
                         </div>
                         <div class="preview-info-item">
                             <span class="preview-info-label">👤 Edited by:</span>
-                            <span class="preview-info-value" id="info-user-{{ content_id }}">{{ latest.user or 'Unknown' }}</span>
+                            <span class="preview-info-value" id="info-user-{{ content_id }}">{{ user_mappings.get(latest.user, latest.user or 'Unknown') }}</span>
                         </div>
                         <div class="preview-info-item">
                             <span class="preview-info-label">🕒 Modified:</span>
@@ -398,7 +398,7 @@
                         {% for edit in data.versions|sort(attribute='version', reverse=True) %}
                         <div class="version-item {% if loop.first %}active{% endif %}" 
                              id="version-{{ content_id }}-{{ edit.version }}"
-                             onclick="event.stopPropagation(); selectVersion({{ content_id }}, {{ edit.version }}, '{{ edit.new_name }}', '{{ edit.user or 'Unknown' }}', '{{ edit.time_of_modification | localtime('%Y-%m-%d %H:%M') if edit.time_of_modification else 'N/A' }}', '{{ edit.created_at | localtime('%Y-%m-%d %H:%M') }}', '{{ url_for('static', filename='uploads/edited_media/' ~ edit.content_id ~ '/' ~ edit.new_name) }}')">
+                             onclick="event.stopPropagation(); selectVersion({{ content_id }}, {{ edit.version }}, '{{ edit.new_name }}', '{{ user_mappings.get(edit.user, edit.user or 'Unknown') }}', '{{ edit.time_of_modification | localtime('%Y-%m-%d %H:%M') if edit.time_of_modification else 'N/A' }}', '{{ edit.created_at | localtime('%Y-%m-%d %H:%M') }}', '{{ url_for('static', filename='uploads/edited_media/' ~ edit.content_id ~ '/' ~ edit.new_name) }}')">
                             <div class="version-thumbnail">
                                 {% if edit.new_name.lower().endswith(('.jpg', '.jpeg', '.png', '.gif', '.webp')) %}
                                 <img src="{{ url_for('static', filename='uploads/edited_media/' ~ edit.content_id ~ '/' ~ edit.new_name) }}"