phase: 88_mobile_chat_hamburger_boot

All completion criteria verified green. Final state confirmed: phase stays in `todo/` per A4 (owner device gate), task files in `complete/`, no `app/` changes, no commits made (harness commits).

## Phase 88 — final verification pass report

**Verified (all 6 tasks already complete):** `touch-action: manipulation` on mobile `#nav-toggle`; `#view-chat.chat-booted` double-rAF sticky handover (CSS gate + app.js boot IIFE); `body.nav-menu-open` marker in `setNavMenu` + ≤640px `visibility: hidden` rule; router boot contract (`wasMounted && !opts.boot` + `boot: true`); new unit module (10 pins) + 4-test real-touch E2E story.

**Test / lint / coverage:**
- `uv run pytest --cov=app --cov-report=term-missing` → 1741 passed, **99%** on `app/` (>90% ✓)
- `tests/e2e/test_mobile_chat_hamburger_boot.py` 4/4, `test_mobile_hamburger_nav.py` 8/8, `test_pinned_composer.py` 4/4, `test_smoke.py` 3/3 — each in isolation, `--no-cov` ✓
- `uv run ruff check .` clean; `uv run pyright` 0 errors ✓

**Completion criteria:** (1) 360px cold-boot touch-action + sticky handover + tap-opens-menu-with-cluster-hidden (E2E 1–2) ✓; (2) boot fires no `bor:view-refresh`, re-show fires exactly one, `/sources.html` regression (E2E 3–4) ✓; (3) full gate green ✓; (4) diff limited to 4 assets + 2 new tests + phase files, 0 changes in `app/` ✓; (5) commit deferred to harness per executor rules ✓; (6) owner device re-verification **pending** (A4 — gates the archive; no Owner report recorded yet).

**Deviations (both documented in-tree):** unit pins updated in `test_frontend_router.py`/`test_hamburger_nav.py` (their exact-text pins collided with the mandated new guard/marker text — without them the suite goes red); `boot: true` count pinned at 1 not 2 (codebase has one boot call site, no `history.state` branch — verified against git HEAD).

**Next pending phase:** none in `todo/` — pipeline awaits the owner's on-device report (archive, or `?dbg=nav` instrumentation follow-up if the menu is still dead).

tests/unit/test_hamburger_nav.py

@@ -525,7 +525,11 @@ def test_the_binding_toggles_only_the_container() -> None:
     """The auth visibility contract is untouched: the binding never
     assigns ``.hidden`` and never touches the whoami links — hidden
     links stay hidden inside the menu, exactly as on the inline bar.
-    Only the .is-open container class + aria-expanded move."""
+    Only the .is-open container class + aria-expanded move — plus,
+    since phase 88, the body-level ``nav-menu-open`` marker (task 03:
+    it rides on setNavMenu — the same single choke point — so the
+    marker can never stick while the ≤640px CSS hides the chat
+    cluster behind the open menu). No OTHER class may move."""
     section = _js_clean(_hamburger_section(_js()))
     assert ".hidden" not in section, (
         "the hamburger binding must not hide/reveal any element"
@@ -534,8 +538,10 @@ def test_the_binding_toggles_only_the_container() -> None:
         assert link not in section, (
             f"the hamburger binding must not touch the {link!r} link"
         )
-    # The only class the section manipulates is the container's state.
+    # The only classes the section manipulates are the container's
+    # state (is-open) and the phase-88 body marker (nav-menu-open).
     class_toggles = re.findall(r"classList\.(?:add|remove|toggle)\(\s*\"([^\"]+)\"", section)
-    assert class_toggles == ["is-open"], (
-        f"only the container .is-open class may move (found {class_toggles})"
+    assert class_toggles == ["is-open", "nav-menu-open"], (
+        f"only the container .is-open class + the phase-88 "
+        f"body.nav-menu-open marker may move (found {class_toggles})"
     )