docs: mark M4 done

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wmy1BpCKi8KeSjaWhYuCPV

docs/ROADMAP.md

@@ -10,14 +10,13 @@ Status legend: ✅ done · 🚧 in progress · ⬜ not started
 
 ## Current state (one line)
 
-✅ **M3 done.** Clockula's alarms ring. Next-fire resolution is a pure function
-over a repeat mask and a zone, DST-correct in both directions; skip and snooze
-each have a persisted watermark; the engine registers only the single next alarm
-via `setAlarmClock`, is driven by five thin receivers, and rings through a
-foreground service that survives process death and reboot and never degrades to
-silence. Schema v2 adds `alarm_states`, and M2's reboot blind spot is closed.
-**M4** (the app shell — navigation host, four tabs, the live pill, and the ring
-screen's UI) is next.
+✅ **M4 done.** Clockula has a face. Four tabs under an M3 Expressive navigation
+bar that becomes a wide rail on a tablet, with the back-stack policy and the
+live pill's whole decision written as pure functions rather than as composable
+state; the ring screen is real, with a maths or hold challenge that always has a
+way out — three wrong answers or sixty seconds, whichever comes first. The tabs
+themselves are still empty states: **M5** (the alarms screen — list, editor,
+time picker, repeat days, per-alarm overrides) is next.
 
 ---
 
@@ -166,7 +165,7 @@ plumbing.
   no device was attached; an auto-silenced alarm is silently missed, with no
   missed-alarm notification until someone asks for one.
 
-### ⬜ M4 — App shell
+### ✅ M4 — App shell
 - Navigation host, four tabs, M3 navigation bar, adaptive rail on wide layouts.
 - The **live pill** (`PLAN.md` §9) — shared running-state surface, pause + stop
   from any tab.
@@ -174,6 +173,35 @@ plumbing.
   dismiss challenge that cannot strand the user.
 - Motion from the kit's `identity` module; predictive back.
 
+  ✅ 480 JVM tests, 154 of them new, and still **no Robolectric** — which had to
+  be earned rather than kept. Everything that decides something moved out of the
+  composables: `ShellNavigation` (what a tab tap does to the back stack, and
+  that back from a tab goes to Alarms while back from Alarms leaves the app),
+  `LivePillSelector` (which of several running things the pill is about),
+  `ClockFormat`, and `ChallengeGate`. The adaptive part is
+  `NavigationSuiteScaffold` taking its own default — the short bar on a phone,
+  the wide rail on a tablet — rather than a hand-rolled width branch that would
+  miss the tabletop posture. The pill shows for paused and expired timers too,
+  not only running ones: pausing from the pill must not make the pill disappear
+  under the thumb that pressed it. Its value comes from the snapshot, so a timer
+  that reaches zero flips to "finished" before M6's expiry write lands. The
+  challenge's escape hatch opens on three wrong answers **or** sixty seconds of
+  ringing, for every challenge kind, asserted as one parameterised invariant;
+  snooze is never gated; a completed hold *is* the dismissal, and an
+  accessibility click completes the hold, because a challenge TalkBack cannot
+  answer is exactly the stranding the requirement forbids. floret-kit went to
+  0.5.0 for one change: `CollapsingScaffold`'s `onBack` is nullable, so a
+  top-level tab draws no back arrow that would pop nothing.
+
+  Knowingly open: M4 ships no in-app way to *start* a timer or the stopwatch, so
+  the live pill cannot be demonstrated by hand until M6/M7 — it is proven by its
+  unit tests and by an instrumentation test that seeds the repository directly,
+  and no debug button was added to paper over it. The nine new instrumentation
+  tests compile in the gate but have never run on hardware, as no device was
+  attached. `POST_NOTIFICATIONS` is asked for once on first launch; explaining a
+  denial, and the exact-alarm and full-screen-intent grant deep links, moved
+  wholly to M10's self-check, which is the screen with room to say why.
+
 ### ⬜ M5 — Alarms screen
 List, create, edit, delete, enable/disable. Time picker, repeat-day selector,
 label, ringtone picker, vibrate, snooze settings, per-alarm overrides. Next-fire