Extension: localized strings ship in the design pack, UI language from the backend

Serve extension design resources from the server as a versioned pack ...

CSS (card + popup), field-detection keyword tables and UI config now ship as
extensions/pack/ with sha256 in pack.json and a monotonic version. The backend
serves pack.json unauthenticated (no-cache) and files versioned/immutable; a
background-worker sync validates schema, ext-version compatibility and hashes,
then stores the pack atomically in chrome.storage.local — content scripts and
the popup only read storage, never fetch, and fall back to the bundled
defaults. Publish tool auto-bumps on content change and writes pack.json last.
Firefox bundle inlines pack-shared.js; release 0.2.0.

E2E (15/15): adoption, live restyle without re-release, rollback and
min-extension guards, sha-mismatch abort, offline fallback. Tests: node 25+21,
pytest 57.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Detect login fields with a scoring classifier instead of heuristics ...

field-detect.js is a pure UMD module: every input becomes a descriptor
(name/id/placeholder/aria-label/label text, visibility state, type,
autocomplete token) scored against multilingual keyword tables with
anti-keywords for traps (search, newsletter, cc, otp and now repeat-
password fields). findLoginTargets pairs one username with one password
per form context, merges confirm-password pairs, and falls back to the
closest preceding input in anonymous SPA forms.

content.js reduces to DOM probing (descriptor building + scan) and the
card/interceptor flow; the manifest loads field-detect.js first.

The module is unit-tested without a browser via tools/test-field-detect.js
(16 plain-node cases over a fake tree) and verified end-to-end in Chromium
on a page mixing russian placeholders, newsletter/search/otp/cc traps and
a confirm-password signup form: three cards, correct pairs, Use fills the
right fields only.

Makefile: the per-file $(SRC) replaces the directory prerequisite (a
stale edit inside src/ never rebuilt the bundles), recipes copy with
cp --parents, and make test runs the node suite.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Render the autofill card in a closed Shadow DOM ...

The card used to be injected straight into the page: host-page CSS could
restyle it (or hide/mimic it), page JS could read the card's DOM — leaking
secret titles — and reach its buttons via querySelector on our class names.

Now it lives in a closed shadow root on a bare sized-to-zero host element:
- CSS does not cross the shadow boundary in either direction, so page styles
  can no longer repaint the card;
- the page cannot traverse into a closed root (host.shadowRoot is null), so
  secret titles and buttons are unreachable from the main world;
- src/content.css is no longer injected into page stylesheets — it is now a
  web-accessible resource, fetched once per page and injected as a <style>
  inside the shadow root (with a graceful no-styles fallback).
- while restyling the card, bring it onto the gnexus-ui-kit 1.0 palette
  (panel #16161e, left accent border, uppercase IBM Plex Mono titles) to
  match the rebuilt popup.

Verified end-to-end in real Chromium: isolation probe reports a bare empty
host, null shadowRoot, no card nodes or CSS rules reachable from the page,
no title leak under deliberately hostile page CSS (color:red !important over
all divs); clicking Use fills the form and removes the card.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Import browser extension source under extensions/extension ...

Move the gnexus-creds-extension sources (Chrome/Firefox MV3) from the
separate sibling repository into extensions/extension/ so builds live
next to the packaged releases this service distributes
 (extensions/dist/ + extensions/manifest.json, untouched).

- add a reproducible `make lib` target materializing lib/ from the
  frontend's pinned gnexus-ui-kit (gitignored, like before)
- drop the playwright-only package.json/lock; system node+zip suffice
- scoped .gitignore so it cannot shadow tracked extensions/dist zips
- README (main + extension): document the in-repo build and publish flow

Rebuilt zips differ from released ones only in the three lib files
(older kit in the release); extension code itself is byte-identical.

Co-Authored-By: Claude Code <noreply@anthropic.com>