feat(clipboard): implement proper Linux file reference clipboard support

src/utils/clipboard.js

@@ -51,12 +51,34 @@ class Clipboard {
       }
     } else if (process.platform === 'linux') {
       try {
-        // Use file:// URI format for Linux clipboard compatibility
         const fileUri = url.pathToFileURL(filePath).toString();
-        await this.copyText(fileUri);
+        const method = Clipboard._detectLinuxClipboardMethod(fileUri);
+
+        if (!method) {
+          // Neither xclip nor wl-copy available; fall back to plain-text URI
+          return this.copyText(fileUri);
+        }
+
+        const result = spawnSync(method.tool, method.args, {
+          input: method.payload,
+          stdio: ['pipe', 'pipe', 'pipe'],
+          timeout: 2000,
+        });
+
+        if (result.error || result.status !== 0) {
+          logger.debug(
+            `Failed to copy file reference using ${method.tool}, falling back to text:`,
+            result.error?.message || `exit code ${result.status}`,
+          );
+          return this.copyText(fileUri);
+        }
       } catch (error) {
-        logger.debug('Failed to copy file URI, falling back to text path:', error.message);
-        return this.copyText(filePath);
+        logger.debug(
+          'Failed to copy file reference on Linux, falling back to text:',
+          error.message,
+        );
+        const fileUri = url.pathToFileURL(filePath).toString();
+        return this.copyText(fileUri);
       }
     } else if (process.platform === 'darwin') {
       try {
@@ -78,6 +100,60 @@ tell app "Finder" to set the clipboard to aFile`;
     }
   }
 
+  /**
+   * Detect the correct Linux clipboard tool, MIME type, and payload for file references.
+   *
+   * Desktop environment detection:
+   * - GTK-based (GNOME, XFCE, Cinnamon, MATE, Budgie): uses `x-special/gnome-copied-files`
+   * - KDE/Qt: uses `text/uri-list`
+   * - Unknown: defaults to GTK format (more widely supported)
+   *
+   * Display protocol detection:
+   * - Wayland ($WAYLAND_DISPLAY set): uses `wl-copy`
+   * - X11 ($DISPLAY set): uses `xclip`
+   * - Neither: returns null (no clipboard tool available)
+   *
+   * @param {string} fileUri - The file:// URI to place on the clipboard
+   * @returns {{ tool: string, args: string[], payload: string } | null}
+   * @private
+   */
+  static _detectLinuxClipboardMethod(fileUri) {
+    const desktop = (process.env.XDG_CURRENT_DESKTOP || '').toUpperCase();
+    const isKDE = desktop.includes('KDE');
+
+    // Determine MIME type and payload based on desktop environment
+    let mimeType;
+    let payload;
+    if (isKDE) {
+      mimeType = 'text/uri-list';
+      payload = `${fileUri}\r\n`;
+    } else {
+      // GTK-based desktops (GNOME, XFCE, Cinnamon, MATE, Budgie) and unknown DEs
+      mimeType = 'x-special/gnome-copied-files';
+      payload = `copy\n${fileUri}`;
+    }
+
+    // Determine clipboard tool based on display protocol
+    if ((process.env.WAYLAND_DISPLAY || '').trim()) {
+      return {
+        tool: 'wl-copy',
+        args: ['--type', mimeType],
+        payload,
+      };
+    }
+
+    if ((process.env.DISPLAY || '').trim()) {
+      return {
+        tool: 'xclip',
+        args: ['-selection', 'clipboard', '-t', mimeType],
+        payload,
+      };
+    }
+
+    // No display server detected
+    return null;
+  }
+
   /**
    * Reveal file in file manager (cross-platform)
    * @param {string} filePath - The file path to reveal