feat: implement file editing capabilities with CodeMirror integration

- Added CodeMirror editor for file content editing in FilesView.
- Introduced draft saving functionality with unsaved changes confirmation dialog.
- Implemented file writing API to persist changes to the filesystem.
- Enhanced language support for syntax highlighting based on file extensions.
- Updated UI components to support new editing features, including save and discard options.
- Refactored line selection logic for improved user experience on both desktop and mobile.
- Added new utility functions for language detection by file extension.
- Introduced a new theme for CodeMirror to align with the application's design.

packages/ui/src/index.css

@@ -46,6 +46,10 @@ textarea[data-chat-input="true"]:hover {
   box-shadow: none;
 }
 
+.oc-cm-selected-line {
+  background: color-mix(in srgb, var(--accent) 70%, transparent);
+}
+
 :root.vscode-runtime textarea[data-chat-input="true"]::placeholder {
   color: color-mix(in srgb, var(--vscode-input-placeholderForeground, var(--muted-foreground)) 65%, transparent);
 }