feat(app): self-heal the stale-shell post-deploy paper-cut

The v1.4.38.3 `AppError` boundary reloads once when a stale shell
trips `ChunkLoadError`, but the reload only fires AFTER the user
hits a navigation that lazy-loads a missing chunk. Users sitting on
the dashboard or insights overview ride out the staleness until
their next click; some never click and the cached shell silently
drifts further out of date with every deploy.

Three layered fixes so the running app heals itself instead:

- `public/sw.js` now keys both `STATIC_CACHE` and `PAGE_CACHE` to
  the app release tag (`v1.4.38.4`). The `activate` step already
  evicts any cache name outside the current pair, so bumping the
  string at release time guarantees the precached root HTML and the
  precached `/_next/static/*` chunks from the previous deploy are
  dropped on the next SW install.
- `next.config.ts` injects `NEXT_PUBLIC_APP_VERSION` from
  `package.json` into the client bundle so the running shell knows
  which release it was built against.
- New `<VersionPoller>` client component mounts inside `<Providers>`
  and polls `/api/version` every 60 s. If the live version moves
  ahead of the shell-baked version it unregisters every active SW,
  wipes CacheStorage, and `window.location.reload()`s.
  `sessionStorage` gates the reload to once per session so a
  mid-deploy webhook race that briefly returns a stale image cannot
  loop the page.

src/components/providers.tsx

@@ -13,6 +13,7 @@ import { I18nProvider } from "@/lib/i18n/context";
 import type { Locale } from "@/lib/i18n/config";
 import { Toaster } from "@/components/ui/sonner";
 import { AppSettingsProvider } from "@/components/app-settings-provider";
+import { VersionPoller } from "@/components/version-poller";
 
 // ── Theme Context ────────────────────────────────────
 
@@ -130,6 +131,7 @@ export function Providers({
           <AppSettingsProvider>
             {children}
             <Toaster position="bottom-right" richColors />
+            <VersionPoller />
           </AppSettingsProvider>
         </I18nProvider>
       </ThemeProvider>

src/components/version-poller.tsx

@@ -0,0 +1,123 @@
+"use client";
+
+import { useEffect } from "react";
+
+/**
+ * v1.4.38.4 — runtime self-heal for the stale-shell post-deploy
+ * paper-cut.
+ *
+ * After a release the cached SPA shell still references the old
+ * chunk filenames; the running React tree lazy-loads them, the new
+ * server 404s them, and the user lands on `ChunkLoadError`. The
+ * v1.4.38.3 `AppError` boundary added a one-shot
+ * `window.location.reload()` for that case, but it only fires AFTER
+ * the user trips the error — typically in the middle of a
+ * navigation flow.
+ *
+ * This component runs the check pro-actively. Every 60 s it fetches
+ * `/api/version` and compares the live version string against
+ * `NEXT_PUBLIC_APP_VERSION` (injected from `package.json` at build
+ * time by `next.config.ts`). When the live version moves ahead of
+ * the running shell:
+ *
+ *   1. Unregister every active service worker so the next page load
+ *      doesn't reinstall the old SW.
+ *   2. Delete every CacheStorage entry so the precached root HTML
+ *      and the `/_next/static/*` chunks from the previous deploy
+ *      can't be served back.
+ *   3. `window.location.reload()` — fetches the fresh shell + new
+ *      chunk graph.
+ *
+ * `sessionStorage` gates the reload to once per session so a misset
+ * version (server briefly serves a stale image, e.g. mid-deploy
+ * webhook race) cannot loop.
+ */
+
+const POLL_INTERVAL_MS = 60_000;
+const SESSION_GUARD_KEY = "healthlog:version-reload-attempted";
+const SHELL_VERSION = process.env.NEXT_PUBLIC_APP_VERSION ?? "";
+
+type VersionEnvelope = {
+  data?: { version?: string };
+};
+
+async function fetchLiveVersion(signal: AbortSignal): Promise<string | null> {
+  try {
+    const res = await fetch("/api/version", {
+      cache: "no-store",
+      signal,
+    });
+    if (!res.ok) return null;
+    const json = (await res.json()) as VersionEnvelope;
+    return json.data?.version ?? null;
+  } catch {
+    return null;
+  }
+}
+
+async function evictAndReload(): Promise<void> {
+  try {
+    sessionStorage.setItem(SESSION_GUARD_KEY, String(Date.now()));
+  } 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.
+  }
+
+  if ("serviceWorker" in navigator) {
+    try {
+      const regs = await navigator.serviceWorker.getRegistrations();
+      await Promise.all(regs.map((r) => r.unregister()));
+    } catch {
+      /* best effort */
+    }
+  }
+
+  if (typeof caches !== "undefined") {
+    try {
+      const keys = await caches.keys();
+      await Promise.all(keys.map((k) => caches.delete(k)));
+    } catch {
+      /* best effort */
+    }
+  }
+
+  window.location.reload();
+}
+
+export function VersionPoller(): null {
+  useEffect(() => {
+    if (!SHELL_VERSION) return;
+    if (typeof window === "undefined") return;
+    try {
+      if (sessionStorage.getItem(SESSION_GUARD_KEY)) return;
+    } catch {
+      /* fall through — we'll try the reload anyway if mismatch hits */
+    }
+
+    const controller = new AbortController();
+
+    async function checkOnce(): Promise<void> {
+      const live = await fetchLiveVersion(controller.signal);
+      if (!live) return;
+      if (live === SHELL_VERSION) return;
+      await evictAndReload();
+    }
+
+    // First check 5 s after mount — gives the app a chance to settle
+    // before we touch caches. Then on the recurring interval.
+    const initial = window.setTimeout(() => void checkOnce(), 5_000);
+    const interval = window.setInterval(
+      () => void checkOnce(),
+      POLL_INTERVAL_MS,
+    );
+
+    return () => {
+      window.clearTimeout(initial);
+      window.clearInterval(interval);
+      controller.abort();
+    };
+  }, []);
+
+  return null;
+}