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.

scripts/package_extension.py

@@ -1,10 +1,11 @@
 #!/usr/bin/env python3
-"""Package the Chrome extension.
+"""Package the browser extension.
 
 Default builds a testing/unpacked-style archive that keeps manifest.key so the
-extension ID stays stable for native messaging. ``--webstore`` writes the same
-runtime files but strips ``key`` from manifest.json because the Chrome Web Store
-rejects that field.
+Chromium extension ID stays stable for native messaging. ``--webstore`` writes
+the same runtime files but strips ``key`` from manifest.json because the Chrome
+Web Store rejects that field. ``--firefox`` writes a Firefox-friendly archive
+with the Gecko extension ID and without Chromium-only manifest keys.
 """
 from __future__ import annotations
 
@@ -26,10 +27,17 @@ RUNTIME_FILES = (
 )
 RUNTIME_DIRS = ("icons",)
 
-def _read_manifest(webstore: bool) -> dict:
+def _read_manifest(webstore: bool, firefox: bool) -> dict:
   manifest = json.loads((EXTENSION_DIR / "manifest.json").read_text(encoding="utf-8"))
-  if webstore:
+  if webstore or firefox:
     manifest.pop("key", None)
+  if firefox:
+    manifest["permissions"] = [p for p in manifest.get("permissions", []) if p != "windows"]
+    manifest["background"] = {"scripts": ["background.js"]}
+    gecko = manifest.setdefault("browser_specific_settings", {}).setdefault("gecko", {})
+    gecko["strict_min_version"] = "140.0"
+    manifest.setdefault("browser_specific_settings", {}).setdefault("gecko_android", {})["strict_min_version"] = "142.0"
+    gecko["data_collection_permissions"] = {"required": ["none"]}
   return manifest
 
 def _copy_tree(src: Path, dst: Path) -> None:
@@ -37,10 +45,12 @@ def _copy_tree(src: Path, dst: Path) -> None:
     shutil.rmtree(dst)
   shutil.copytree(src, dst)
 
-def package_extension(*, webstore: bool = False, out: Path | None = None) -> Path:
-  manifest = _read_manifest(webstore)
+def package_extension(*, webstore: bool = False, firefox: bool = False, out: Path | None = None) -> Path:
+  if webstore and firefox:
+    raise ValueError("--webstore and --firefox are mutually exclusive")
+  manifest = _read_manifest(webstore, firefox)
   version = manifest["version"]
-  suffix = "webstore" if webstore else "testing"
+  suffix = "firefox" if firefox else "webstore" if webstore else "testing"
   out = out or DIST_DIR / f"browser-cli-extension-{suffix}-v{version}.zip"
   staging = DIST_DIR / f"extension-package-{suffix}"
 
@@ -70,9 +80,10 @@ def package_extension(*, webstore: bool = False, out: Path | None = None) -> Pat
 def main() -> None:
   parser = argparse.ArgumentParser(description="Package browser-cli extension")
   parser.add_argument("--webstore", action="store_true", help="strip manifest.key for Chrome Web Store upload")
+  parser.add_argument("--firefox", action="store_true", help="build a Firefox-friendly extension zip")
   parser.add_argument("--out", type=Path, default=None, help="output zip path")
   args = parser.parse_args()
-  print(package_extension(webstore=args.webstore, out=args.out))
+  print(package_extension(webstore=args.webstore, firefox=args.firefox, out=args.out))
 
 if __name__ == "__main__":
   main()