fix(insights): make per-category status cards read-only so navigation never blocks on the LLM

Opening an Insights category page froze the whole UI: the per-metric
status card fired a cold, uncapped LLM fetch on mount with no client
abort, so the request hung up to the server's 60s ceiling and the
pending/resolve re-renders thrashed the tab strip and ate touch events.
Timeouts were never negatively cached, so every visit re-blocked.

Fix the class holistically:

- Bound every status GET on the client. The shared use-insight-status
  hook and the inline medication-compliance query now wrap fetch in an
  8s AbortController and stop retrying inline; navigation can no longer
  await an uncapped round-trip.

- Make the status routes read-only. On a cache miss the generator
  enqueues an out-of-band pg-boss job (insight-status-generate) and
  returns a preparing envelope; the client polls a bounded interval
  until the worker warms the cache. Models the dashboard snapshot's
  ready/preparing pattern. The queue is registered in the worker
  allQueues loop + a boss.work handler, with a guard test.

- Fix the nightly warm-pass regression: warm every supported locale
  (the client reads against the active UI locale, not the persisted
  User.locale) and warm on a cached comprehensive outcome too (its
  write still evicts the per-status caches). Add a short-TTL negative
  cache on the timeout path so a transient provider stall no longer
  makes every subsequent visit re-block or re-enqueue.

- Add loading.tsx for the insights segment + the root so any future
  RSC await streams a skeleton instead of blocking the transition.

- Stabilise the advisor regenerate callback so a status-query flip
  can't re-render the memoised tab strip mid-gesture.

New i18n key insights.assessmentPreparing across all six locales.

src/app/loading.tsx

@@ -0,0 +1,24 @@
+/**
+ * v1.8.3 — root-level loading skeleton (dashboard segment + any top-level
+ * route without its own `loading.tsx`).
+ *
+ * Defense-in-depth for the navigation-freeze class: a segment that streams
+ * paints this tile-grid skeleton instead of a blank frame. Pure server
+ * component — no client hooks, no data fetch. More specific segments (e.g.
+ * `/insights`) provide their own skeleton and take precedence.
+ */
+export default function RootLoading() {
+  return (
+    <div data-slot="dashboard-loading" className="space-y-6 p-4">
+      <div className="bg-muted h-7 w-44 animate-pulse rounded motion-reduce:animate-none" />
+      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-3">
+        {Array.from({ length: 6 }).map((_, i) => (
+          <div key={i} className="bg-card rounded-xl border p-4">
+            <div className="bg-muted mb-3 h-4 w-24 animate-pulse rounded motion-reduce:animate-none" />
+            <div className="bg-muted/60 h-24 w-full animate-pulse rounded-lg motion-reduce:animate-none" />
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}