[kermitsxb]

Summary

Firefox support for the GitHub → Orca extension, using the same native host as Chrome and Arc.

• Build: npm run build also produces extension-firefox/ (git-ignored). Its manifest is derived from extension/manifest.json by scripts/firefox-manifest.mjs. The derived manifest uses background.scripts, drops key, adds options_ui, and sets browser_specific_settings.gecko (id github-orca@stocki, min 128, data_collection_permissions: none).
• Signing: npm run sign:firefox runs web-ext sign --channel=unlisted with WEB_EXT_API_KEY / WEB_EXT_API_SECRET and writes the .xpi to web-ext-artifacts/. npm run lint:firefox runs web-ext lint. Both scripts rebuild first.
• Host registration: scripts/install.sh also writes ~/Library/Application Support/Mozilla/NativeMessagingHosts/com.stocki.github_orca.json with allowed_extensions. Host code is unchanged.
• Error mapping: the background worker reads Firefox's port.error. Firefox's "No such native application" and "does not have permission" messages now map to the same toasts as on Chrome.
• Docs: README has a Firefox install section (signing, .xpi, temporary load, permissions troubleshooting). AGENTS.md is updated.

Verification

• npm test passes (229 tests), npm run typecheck is clean and npm run build succeeds.
• npm run lint:firefox reports 0 errors and 2 warnings. data_collection_permissions only exists from Firefox 140 (Android 142), but strict_min_version is 128. Older versions ignore the key, so the warnings are accepted.
• install.sh was run against a sandbox HOME in three setups: Chrome and Mozilla dirs, Mozilla only, and no browser dirs. The no-browser setup fails with the expected message. The script was not run against the real HOME.

Not verified (manual)

• Run ./scripts/install.sh, then load extension-firefox/ via about:debugging.
• Check Review in Orca and Clone in Orca on github.com.
• Run one slow clone that takes over 30 s, to check that Firefox keeps the event page alive while the native port is open.
• Sign with npm run sign:firefox and install the .xpi in Firefox release.