support for firefox - claude did 2 days of work in 15m?

[macgyver]

Summary

Adds first-class Firefox 121+ support alongside the existing Chromium build. Same source, dual build pipeline, dual zip in every release.

Originally opened by a contributor with the working baseline (polyfill + gecko block + manifest postbuild). Pushed a follow-up commit that hardened it: target-aware tooling, full test coverage of the manifest contract, documentation parity for end-users, and CI that ships both zips.

What's in the branch

Code

• webextension-polyfill (runtime): every chrome.* import → import browser from 'webextension-polyfill'. Promise-based on both browsers, behavior identical on Chromium.
• src/manifest.ts: branches on process.env.TARGET === 'firefox'. Firefox build adds browser_specific_settings.gecko (id, strict_min_version: 121.0, data_collection_permissions: { required: ['none'] }); Chromium build keeps minimum_chrome_version: 116. Manifest description capped at 132 chars (CWS + AMO ceiling) with a build-time guard.
• scripts/firefox-manifest.mjs (new, pure helper): rewrites background.service_worker → background.scripts (array, type: 'module' preserved) and strips Chromium-only use_dynamic_url from web_accessible_resources. Throws if there's no service_worker to rewrite — silent no-op there would ship a broken Firefox build.
• scripts/firefox-postbuild.mjs: now a thin file-IO wrapper around the helper. Runs after vite build when TARGET=firefox.
• scripts/zip-extension.mjs: target-aware "Next steps" output — Chromium gets chrome://extensions / Load unpacked, Firefox gets about:debugging / Load Temporary Add-on plus the temporary-install caveat and the Developer-Edition-with-signatures-off path. Verify-manifest-at-root error message now mentions both stores + both rebuild commands.
• vite.config.ts: outDir switches to dist-firefox/ when TARGET=firefox.
• eslint.config.js / .gitignore / .prettierignore: pick up dist-firefox/ alongside dist/.

CI

• .github/workflows/release.yml now builds + packages BOTH targets and attaches both zips to the draft GitHub release. Uses the same npm run zip[:firefox] scripts as locally so the manifest-at-root verification + sourcemap stripping run in CI exactly as they do on a dev machine.

Tests (+9, total 176)

• tests/scripts/firefox-manifest.test.ts (5): rewrite swaps service_worker → scripts with type: 'module' preserved; throws when there's no service_worker to rewrite; strips use_dynamic_url from every WAR entry; no-ops on missing WAR; mutates in place + returns same reference.
• tests/manifest.test.ts (4): default build adds minimum_chrome_version + omits gecko; TARGET=firefox adds full gecko block + omits minimum_chrome_version (mutual exclusion); shared MV3 fields stay identical between targets; description respects the 132-char store ceiling.

Docs

• README.md: full Firefox install/update section parallel to the Chromium one — Option A (temporary add-on, any FF 121+, resets on restart) and Option B (persistent on Developer Edition / Nightly: xpinstall.signatures.required = false + .zip → .xpi rename). Troubleshooting table gains the Firefox "extension appears to be corrupt" row. Scripts table covers build:firefox / zip:firefox / release:dry:firefox. Releasing section explains the dual-target CI flow. Architecture comment notes manifest.ts's TARGET branching.
• PRIVACY.md: storage area names use the cross-browser form (storage.sync / storage.local); permission justifications mention both chrome.tabs.captureVisibleTab and browser.tabs.captureVisibleTab; remote-code section calls out both build commands.

Local commands

# Chromium build + zip
npm run release:dry         # → clay-slip-vX.Y.Z.zip

# Firefox build + zip (post-build rewrite included)
npm run release:dry:firefox # → clay-slip-vX.Y.Z-firefox.zip

Verification

• npm run validate → typecheck / lint / format / 176 tests green.
• npm run release:dry + npm run release:dry:firefox → both succeed.
• Zip contents inspected:
  • Chromium: background.service_worker, minimum_chrome_version: 116, no gecko block.
  • Firefox: background.scripts: [...] (type: 'module' preserved), no minimum_chrome_version, full gecko block with data_collection_permissions: { required: ['none'] }, zero use_dynamic_url leftovers in WAR.

Install for testers

Firefox 121+ (any channel)

1. Download clay-slip-vX.Y.Z-firefox.zip from the next release and unzip.
2. about:debugging#/runtime/this-firefox → Load Temporary Add-on… → pick the unzipped manifest.json.

(Resets on browser restart. For persistent install, see README → Install → Firefox → Option B.)

Chromium (Chrome / Edge / Brave / Arc / Vivaldi / Opera)

Unchanged from before — clay-slip-vX.Y.Z.zip + chrome://extensions → Load unpacked.

[jjpaulino]

Oh amazing! Give me a chance to test the functionality and we can merge and release no biggie! 🍕