fix(ui): announce failures, keep focus honest and stop the last layout shifts

Hidden states of the floating coach button now leave the tab order and
accessibility tree, its focus ring carries an offset, its icon is dark
on the gradient, an unread nudge is announced once via a live region,
and it sits correctly above the fold on tablet widths and yields to
the onboarding tour. Chart error cards announce themselves, share the
exact height variables of the skeleton band, carry per-chart retry
labels, and a failed chunk renders inside the regular card shell. The
header icon cluster spaces its extended hit areas apart, the tab strip
keeps horizontal paint room for focus rings, the streak row reserves
its slot in every card state, the selection bar clears the bottom nav
on landscape phones, and the version poller keeps an in-memory reload
guard for browsers that block session storage. Mood notes render as
plain paragraphs with a toggle that appears only when text is actually
clamped, the remember control reveals on hover and hands focus to its
confirmation, and the hypnogram names its source and paints only the
lanes the night contains.

src/components/version-poller.tsx

@@ -77,13 +77,21 @@ async function fetchLiveVersion(signal: AbortSignal): Promise<string | null> {
   }
 }
 
+// In-memory mirror of the session guard: under strict-privacy modes
+// sessionStorage throws, and without a fallback a persistent
+// shell/live mismatch (misconfigured build) would reload every poll.
+// Module scope survives re-renders but not the reload itself — after
+// a reload the storage read is retried first, so the mirror only has
+// to break the loop within one document lifetime.
+let inMemoryReloadGuard: string | null = null;
+
 async function evictAndReload(targetVersion: string): Promise<void> {
+  inMemoryReloadGuard = targetVersion;
   try {
     sessionStorage.setItem(SESSION_GUARD_KEY, targetVersion);
   } catch {
-    // sessionStorage can throw under strict-privacy modes; fall
-    // through to the reload anyway — worst case the next deploy
-    // re-triggers the same heal flow.
+    // sessionStorage can throw under strict-privacy modes; the
+    // in-memory mirror above still breaks same-document loops.
   }
 
   if ("serviceWorker" in navigator) {
@@ -120,8 +128,9 @@ export function VersionPoller(): null {
       try {
         lastReloadedFor = sessionStorage.getItem(SESSION_GUARD_KEY);
       } catch {
-        /* fall through — treat as "no attempt recorded" */
+        /* storage unavailable — the in-memory mirror still applies */
       }
+      lastReloadedFor ??= inMemoryReloadGuard;
       const decision = resolveVersionPollDecision(
         live,
         SHELL_VERSION,