docs(testing): web e2e lane docs + Agent Note to implemented

testing.md gains the web browser snapshot tier entry (divergent
DSH_SNAPSHOT=... test:web commands) and names apps/web/tests/snapshots/
as the web surface's snapshot home. The GUI testing note's tier map and
lane map gain the e2e scenarios (both languages, pair re-recorded) and
drop the stale verify-session-real references (those scripts left with
the missions/ tree). packages/client/AGENTS.md check ladder covers the
wire-carriage trigger and refresh/record commands. acp-snapshot README
stops claiming the whole package is ACP-specific — its normalizers are
transport-neutral with three consumers now. vitest.web.config.ts header
carries TODO(ci-browser) with the staged-reversal pointer.

The design-study Agent Note moves proposed/ -> implemented/ rewritten in
present tense: all review decisions recorded (llm:false seam over the
placeholder-key hack, providers-mode replay, whenIdle barrier stack,
single aria golden + anchors, TUI-style inline modes over a suite
factory, scrub-only header stance, CI deferral) with re-entry triggers
under Deferred.

vitest.web.config.ts

@@ -1,10 +1,13 @@
 import tsconfigPaths from 'vite-tsconfig-paths'
 import { defineConfig } from 'vitest/config'
 
-// Web smoke lane (GUI, gate-exempt — not part of the CI sequence yet): built
-// page + real chromium, so it lives outside the unit/e2e includes. The
-// real-host test self-skips without DEEPSEEK_API_KEY; the fixture test is
-// keyless and deterministic.
+// Web browser lane (GUI, gate-exempt — not part of the CI sequence yet):
+// built page + real chromium, so it lives outside the unit/e2e includes. The
+// real-host smoke self-skips without DEEPSEEK_API_KEY; the fixture smoke and
+// the replayed e2e scenarios are keyless and deterministic.
+// TODO(ci-browser): running this lane in CI requires chromium provisioning
+// and reverses the no-browser-in-CI ruling — staged criteria in
+// .agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md.
 try {
   // Node >= 21.7 native; throws when the file does not exist.
   process.loadEnvFile(new URL('.env', import.meta.url).pathname)