test: containerized Chrome end-to-end harness that drives the real popup (closes #181)

`make check` was green while the AddToken screen crashed on every open.
`script/lint` is only `prettier --check`, so a used-but-not-imported
identifier is invisible until a browser evaluates it. This adds a suite
that runs the real popup in a real Chrome and treats any uncaught page
error or console.error as a failure.

- `script/test-e2e` (with `make test-e2e` as a thin shim) builds
  `dist/chrome/` and runs `tests/e2e/run.js` inside the Playwright image,
  pinned by digest. `playwright-core` is pinned to the matching 1.56.0
  through `yarn.lock`; the two must be bumped together because the
  browsers ship inside the image.
- Deliberately outside `script/test` and `script/check`: REPO_POLICIES
  caps `make test` at 20 seconds. Nothing under `tests/e2e/` is named
  `*.test.js`, so jest cannot pick it up either.
- Launches with `channel: "chromium"`; the default headless shell
  silently refuses to load extensions with no error at all. The extension
  id is read from the service worker URL, never hardcoded.
- All http(s) traffic is intercepted at the browser level and served from
  fixtures, so the run is deterministic and offline. Unrecognised
  outbound requests are reported as failures rather than allowed.
- A missing build or an unavailable container fails loudly; a skip that
  looks like a pass is the failure mode this is meant to prevent.
- One allowlisted page error, for the libsodium WASM CSP fallback tracked
  as #182, which is otherwise untouched here.

The suite was demonstrated failing against the unfixed tree with
`pageerror: showView is not defined` and `pageerror: addressDotHtml is
not defined`, so it carries the two one-line import fixes it caught:

closes #150 — `showView` restored to the destructure in
`src/popup/views/addToken.js`, dropped by a22f33d, which made the
AddToken screen unreachable and corrupted the navigation stack.

closes #151 — `addressDotHtml` restored in
`src/popup/views/transactionDetail.js`, dropped by df031fd, which threw
before `showView("transaction")` for every ERC-20 transfer. The shared
`renderAddressHtml` helper is not used here on purpose: it hardcodes the
`/address/` explorer URL, and this row needs the token-specific `/token/`
link.

TODO.md

@@ -10,21 +10,27 @@
 
 # Status
 
-pre-1.0. Tagged v0.1.0 on 2026-02-27. Active development on branch
-feat/issue-144-settings-about (another agent working as of 2026-07-06). Full
-policy file set present; make check on main not verified.
+pre-1.0. Tagged v0.1.0 on 2026-02-27. Working toward the 1.0.0 milestone. Full
+policy file set present. `make check` is green on this branch; a real browser
+end-to-end suite (`make test-e2e`) now exists alongside it, because `make check`
+cannot see a runtime `ReferenceError` in a popup view.
 
 # Next Step
 
-Land feat/issue-144-settings-about: finish the settings About well (build info,
-app name and repo link, release date, version click easter egg, git info derived
-inside Docker), resolve the untracked scripts/ directory (commit or gitignore),
-get review, merge to main.
+Verify `main` passes `make check` after this branch merges and fix anything red;
+`main` must always be green.
 
 # Completed Steps
 
+- 2026-08-09 Containerized Chrome end-to-end harness (`make test-e2e` /
+  `script/test-e2e`) driving the real popup with all network intercepted, plus
+  the two used-but-not-imported crashes it caught: AddToken unreachable (#150)
+  and TransactionDetail broken for every ERC-20 transfer (#151). Harness
+  demonstrated failing before the fixes and passing after (#181).
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
   shims, README Entrypoints section
+- 2026-08-09 Landed the settings About well (build info, app name and repo link,
+  release date, version click easter egg) as `23aeae4` (#145).
 - 2026-03-01: About well in settings with build info and easter egg (in flight
   on feature branch); USD display suppressed on testnets (#142); estimated USD
   for ETH in approve-tx view (#141).
@@ -45,9 +51,12 @@ get review, merge to main.
 
 # Future Steps
 
-- Verify main passes make check after the feature branch merges (not verified
-  2026-07-06 because an agent was active in the tree); fix anything red. main
-  must always be green.
+- Decide the libsodium backend that actually ships (#182) and delete the single
+  allowlist entry it owns in `tests/e2e/harness.js`.
+- Extend the end-to-end suite to the dApp approval signing path (EIP-1193
+  through the real content script, background worker and approval popup), and
+  decide separately whether docker-in-docker makes `make test-e2e` runnable in
+  the Gitea workflow.
 - Prune stale branches: dozens of merged local and remote feature branches
   remain (fix/_, feature/_, tx-\*); delete merged ones locally and on origin.
 - Continue the issue backlog toward a feature-complete wallet, then cut further