build: run the browser e2e suites in CI (closes #259)

Nothing automatic ran either e2e suite, so every browser-level guarantee in this
wallet -- WebAssembly under the shipped CSP, the recovery-phrase and private-key
DOM wipes, the ConfirmTx spend gate, the dApp approval round trips -- held only
when a human or an agent remembered to run it by hand.

.gitea/workflows/e2e.yml adds two jobs, e2e-chrome and e2e-firefox, one per
browser so a Chrome failure cannot hide the Firefox result. They are separate
from the check workflow: REPO_POLICIES.md caps make test at 20 seconds and
script/cibuild is a docker build whose Dockerfile runs make check, so neither the
cap nor the local fast path is touched. make check is byte-for-byte unchanged.

Neither suite could run on the runner as it stood, and the reason is not
docker-in-docker. The runner executes a job inside a container against the HOST's
docker daemon, and the job's checkout lives on a docker volume rather than a host
path, so `docker run -v "$PWD:/work"` is resolved by the host, silently succeeds
and mounts an empty directory -- measured on this runner. The runner image's node
is also too old to install this repo's dependencies. Both suites therefore ship
the repo to the daemon as a build context and build the extension inside the
pinned image, which leaves docker as the only prerequisite on a runner or a
laptop. The suites themselves are unchanged; only how the repo reaches the
container is.

Both scripts now build with --iidfile and run the image by ID rather than by tag,
so two clones running a suite at once on the same host cannot swap it under each
other.

The jobs report, they do not gate. Whether a check blocks a merge is Gitea branch
protection, which this repo does not configure, so a failure is a red mark a
reviewer must account for. Nothing can pass vacuously: no continue-on-error, no
`|| true`, and both scripts exit non-zero when docker is missing, when the image
build fails and when the browser fails to start.

TODO.md

@@ -33,7 +33,8 @@ The backlog lives on the
 authoritative; this file does not duplicate it. Full policy file set present.
 Real-browser end-to-end suites (`make test-e2e` for Chrome,
 `make test-e2e-firefox` for Firefox) now sit alongside `make check`, which
-cannot see a runtime `ReferenceError` in a popup view.
+cannot see a runtime `ReferenceError` in a popup view, and
+`.gitea/workflows/e2e.yml` runs both of them on every push.
 
 # Next Step
 
@@ -45,6 +46,23 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-14: CI runs the browser end-to-end suites. `.gitea/workflows/e2e.yml`
+  runs `script/test-e2e` and `script/test-e2e-firefox` as two jobs on every
+  push, separate from `check`, so `make check` and its 20-second `make test` cap
+  are untouched. Every browser-level guarantee in this repo — the WASM-under-CSP
+  check, the recovery-phrase and private-key DOM wipes, the ConfirmTx spend
+  gate, the dApp approval round trips — was enforced only when a human
+  remembered to run it by hand. The suites could not run on the runner as they
+  stood: the runner executes a job in a container against the host's docker
+  daemon, so `docker run -v "$PWD:/work"` mounts an empty directory (measured),
+  and the runner image's node cannot install this repo's dependencies. Both
+  suites now ship the repo to the daemon as a build context and build the
+  extension inside the pinned image, so docker is the only prerequisite on a
+  runner or a laptop, and both run the image by ID rather than by tag so
+  concurrent clones cannot swap it. The jobs report rather than gate — this repo
+  configures no branch protection — and a deliberately broken assertion was
+  pushed to a scratch branch to prove the job goes red
+  ([#259](https://git.eeqj.de/sneak/AutistMask/issues/259)).
 - 2026-08-12: EIP-1193 error codes now reach the page. `src/content/inpage.js`
   rebuilt every failure as `new Error(error.message)`, so the code the
   background produced and the content script relayed intact was dropped in the
@@ -351,9 +369,5 @@ tracker.
 - Pre-1.0 security review of the extension (key handling, DEBUG mode policy, RPC
   input validation) before any 1.0rc tag. Individual filed issues are parts of
   it, but the review is broader than any of them.
-- Decide whether docker-in-docker makes `make test-e2e` and
-  `make test-e2e-firefox` runnable in the Gitea workflow. Extending the Chrome
-  suite itself is tracked as
-  [#183](https://git.eeqj.de/sneak/AutistMask/issues/183).
 - Cut 1.0.0 once the milestone is empty, then continue tagging as milestones
   land.