test(web): lifecycle & chrome scenarios — workspace flow, reload recovery, dark mode

One tiny recorded text turn drives three whole-page concerns:

- workspace flow over the real wire: the empty-state hero's first send
  materializes a real Workspace + Session (the jsdom workspace-flow suite
  pins this state machine over the fixture client; this scenario pins it
  through HTTP RPC + SSE + the gateway). Durable proof: the session
  header's cwd is the create-by-name target <workspaceRoot>/workspace.
  Adds the hero waiting-state aria golden.
- reload recovery: collapse the sidebar (persisted dsh.layout.panels),
  page.reload, and the surface comes back whole from persistence alone —
  layout collapsed, selection restored (dsh.sessions.current), the
  recorded turn re-rendered from session.history with zero model calls
  (the drained replay cursor makes any stray request fail loud at close).
- dark mode: no product control flips the theme yet, so the scenario
  drives the ThemeService's entire DOM contract — body[data-ds-dark-theme]
  — and pins the shipped cascade: the alias token flips, a painted surface
  repaints, and removing the attribute restores the light sample exactly.
  TODO(web-theme-gesture) upgrades to a real settings control; no theme
  golden per the lane's scope ruling (aria is color-blind).

Agent Note scenario list extended in both languages; pairing re-recorded.

.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md

@@ -48,6 +48,7 @@ The typecheck plane split is structural: the three files that boot the host spin
 4. **`question-composer`** — the shipped composition's resident `ask_user_question` takeover: a recorded turn blocks mid-step on the real userInteraction seam, the composer (`[data-question-key]`) renders in the browser, the test answers through it (the ONE sanctioned place a drive step reacts to model content: the turn cannot complete without the answer, in record and replay alike), and the tool result carries the chosen label. Golden: the composer's stable waiting state.
 5. **`steering`** — mid-turn steer while the question composer blocks the step (the deterministic mid-turn window; no timing dependence). The composer locks while running, so the steer POSTs `session.prompt` `mode:'steer'` from the page over the same same-origin `/api` wire the client uses (`TODO(web-steer-composer)`: drive a composer gesture once one exists); everything downstream is product — gateway → `Agent.steer` → step-boundary drain → durable `steering/message` → SSE → badged interjection bubble. Record-mode fixture honesty: the recording is rejected unless the live model's final reply obeys an instruction only the steering message carries.
 6. **`navigation-panes`** — one rich two-turn seed (turn 1: bash + two parallel reads in one assistant message; turn 2: a markdown-heavy reply) rendered cold through the seeded-history pattern (zero model calls), serving four surfaces: sidebar search (client-side title filter — asserted only after the durable title lands with the attach baseline, because a cold `SessionSummary` carries no title and search matches the `displayTitle` the user sees; negative query empties the tree, positive narrows, clear restores), the Trajectory tab (turn sections + the step group's tool mix plus the view-area aria golden), the Waterfall tab (span stats + one lane per span — the P-I fold counts a turn-0 prologue span because only assistant/steering nodes carry a turn number, pinned as-is), and the details column (the bash toolview row routes click to openDetails; open/closed is asserted on the frame's `data-details-collapsed` attribute because close collapses the grid column to width 0 without unmounting the subtree).
+7. **`lifecycle-chrome`** — one tiny recorded text turn drives three whole-page concerns. Workspace flow over the real wire: the empty-state hero's first send materializes a real Workspace + Session (the jsdom `workspace-flow.snapshot.ts` suite pins this state machine over the fixture client; this scenario pins it through HTTP RPC + SSE + the gateway), proven durably by the session header's cwd being the create-by-name target `<workspaceRoot>/workspace`, plus the hero waiting-state aria golden. Reload recovery: collapse the sidebar (persisted `dsh.layout.panels`), `page.reload`, and the surface comes back whole from persistence alone — layout collapsed, selection restored (`dsh.sessions.current`), the recorded turn re-rendered from `session.history` with zero model calls (the drained replay cursor makes any stray request fail loud at close). Dark mode: no product control flips the theme yet, so the scenario drives the ThemeService's entire DOM contract — the `body[data-ds-dark-theme]` attribute — and pins the shipped cascade: the alias token flips, a painted surface repaints, and removing the attribute restores the light sample exactly (`TODO(web-theme-gesture)` upgrades to a real settings control); per the scope ruling there is no theme/layout golden (aria is color-blind).
 
 ### CI stance