feat(extension): add Firefox WebExtension support

- Add a neutral WebExtension API adapter that uses Firefox browser.* or Chromium chrome.* without mutating globals.
- Switch extension runtime code to the adapter and add Firefox-specific typings for tabs, windows, tab groups, storage, scripting, and native messaging ports.
- Fix Firefox temporary add-on instructions to load the packaged manifest with background.scripts instead of the Chromium service worker manifest.
- Detect Firefox in clients.list via runtime.getBrowserInfo and keep Chromium user-agent fallback support.
- Make navigate.open wait briefly for Firefox to replace initial about:blank with the requested URL.
- Add JS coverage for API selection, clients.list browser detection, and Firefox navigate.open URL polling.
- Bump package and extension version to 0.15.2.

extension/src/commands/windows.ts

@@ -1,3 +1,5 @@
+import { webExtApi as api } from '../browser-api';
+import type { WindowCreateData } from '../types';
 import { getAliases } from '../core';
 import { CommandGroup } from '../classes/CommandGroup';
 import type { CommandEntry } from '../classes/CommandGroup';
@@ -13,7 +15,7 @@ export class WindowsCommands extends CommandGroup {
   };
 
   private async windowsList() {
-    const windows = await chrome.windows.getAll({ populate: true });
+    const windows = await api.windows.getAll({ populate: true });
     const aliases = await getAliases();
     return windows.map(w => ({
       id: w.id,
@@ -27,19 +29,19 @@ export class WindowsCommands extends CommandGroup {
   private async windowsRename({ windowId, name }: WindowsRenameArgs) {
     const aliases = await getAliases();
     aliases[windowId] = name;
-    await chrome.storage.local.set({ windowAliases: aliases });
+    await api.storage.local.set({ windowAliases: aliases });
     return { windowId, name };
   }
 
   private async windowsClose({ windowId }: WindowsCloseArgs) {
-    await chrome.windows.remove(windowId);
+    await api.windows.remove(windowId);
     return { windowId };
   }
 
   private async windowsOpen({ url }: WindowsOpenArgs) {
-    const createData: chrome.windows.CreateData = { focused: true };
+    const createData: WindowCreateData = { focused: true };
     if (url) createData.url = url;
-    const w = await chrome.windows.create(createData);
+    const w = await api.windows.create(createData);
     return { id: w.id };
   }
 }