feat: add Firefox extension support

- Add Firefox as an install target with native messaging manifest support.
- Generate Firefox-specific extension packages with Gecko metadata and AMO-compatible manifest transforms.
- Keep tab group commands available in Firefox through dynamic tab group API helpers.
- Avoid Firefox linter warnings for static tab group API references and direct eval tokens.
- Add Firefox packaging and installer regression coverage.
- Bump the package and extension version to 0.15.1.

tests/test_cli.py

@@ -87,7 +87,7 @@ def test_install_help_lists_supported_browsers():
   result = CliRunner().invoke(main, ["install", "--help"])
 
   assert result.exit_code == 0
-  assert "[chrome|chromium|brave|edge|vivaldi]" in result.output
+  assert "[chrome|chromium|brave|edge|vivaldi|firefox]" in result.output
 
 def test_install_writes_testing_and_webstore_allowed_origins(tmp_path):
   manifests = []
@@ -117,6 +117,31 @@ def test_install_writes_testing_and_webstore_allowed_origins(tmp_path):
   assert "Testing extension ID" in result.output
   assert "Chrome Web Store extension ID" in result.output
 
+def test_install_writes_firefox_allowed_extensions(tmp_path):
+  manifests = []
+
+  def fake_install_manifest(_browser, _host_exe, manifest):
+    manifests.append(manifest)
+    return [tmp_path / "com.browsercli.host.json"]
+
+  with patch("browser_cli.commands.install.native_host_exe", return_value=tmp_path / "browser-cli-native-host"), patch(
+    "browser_cli.commands.install.write_native_host_exe"
+  ), patch("browser_cli.commands.install._install_manifest", side_effect=fake_install_manifest):
+    result = CliRunner().invoke(main, ["install", "firefox"])
+
+  assert result.exit_code == 0
+  assert manifests == [
+    {
+      "name": "com.browsercli.host",
+      "description": "browser-cli native messaging host",
+      "path": str(tmp_path / "browser-cli-native-host"),
+      "type": "stdio",
+      "allowed_extensions": ["browser-cli@yiprawr.dev"],
+    }
+  ]
+  assert "about:debugging#/runtime/this-firefox" in result.output
+  assert "Firefox extension ID" in result.output
+
 def test_install_windows_registers_native_host(tmp_path):
   writes = []