security: open-file IPC blocks executable extensions

Companion to 4.6.61. The open-file IPC handler (used by the
"Open file" buttons in the queue + archive) was previously a
plain shell.openPath call with only an existsSync check:

  if (typeof filePath !== "string" || !filePath) return false;
  if (!fs.existsSync(filePath)) return false;
  const result = await shell.openPath(filePath);

shell.openPath happily launches any path the OS knows how to
execute. An XSS landing through e.g. a smuggled queue item URL
that reached the renderer-side openFile global function could
pass `C:\\Windows\\System32\\calc.exe` and the IPC would launch
calc.

Added a deny-list of obvious shell-execution extensions (.exe,
.bat, .cmd, .com, .ps1, .vbs, .vbe, .js, .jse, .wsf, .wsh, .scr,
.msi, .msp, .lnk, .cpl, .reg, .hta, .jar, .application). Rejected
calls log to debug + return false to the renderer. Media + text +
image extensions remain unaffected — those open in their normal
default-app viewers, which is the intended use case.

show-in-folder + open-folder stay permissive on extension since
they only open File Explorer (no execution).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/main.ts

@@ -6919,9 +6919,24 @@ ipcMain.handle('open-folder', (_, folderPath: string) => {
     }
 });
 
+// Extensions that shell.openPath would happily execute via the system
+// default. Calc.exe via XSS smuggling is the canonical example; this
+// list blocks the obvious vectors. Media/text/image extensions are
+// still fine — shell.openPath opens them in the OS's default viewer.
+const OPEN_FILE_BLOCKED_EXTENSIONS = new Set([
+    '.exe', '.bat', '.cmd', '.com', '.ps1', '.vbs', '.vbe',
+    '.js', '.jse', '.wsf', '.wsh', '.scr', '.msi', '.msp',
+    '.lnk', '.cpl', '.reg', '.hta', '.jar', '.application'
+]);
+
 ipcMain.handle('open-file', async (_, filePath: string): Promise<boolean> => {
     if (typeof filePath !== 'string' || !filePath) return false;
     if (!fs.existsSync(filePath)) return false;
+    const ext = path.extname(filePath).toLowerCase();
+    if (OPEN_FILE_BLOCKED_EXTENSIONS.has(ext)) {
+        appendDebugLog('open-file-rejected-extension', { ext, path: filePath.slice(0, 200) });
+        return false;
+    }
     const result = await shell.openPath(filePath);
     // shell.openPath returns '' on success, an error string on failure.
     return result === '';