feat(insights): wire Coach drawer into /insights via hero strip

Closes the loop between the hero strip's "Ask the coach" /
suggested-prompt chips and the Coach drawer:

- `<HeroStrip>` gains an `onAskCoach` prop. When supplied, the
  "Ask the coach" button drops its disabled state + Coming-soon
  tooltip and clicking calls the handler. Older parents that
  haven't adopted the drawer still get the disabled affordance —
  no breaking change.
- `<SuggestedPrompts>`'s `onPick` already routed up via
  `onPickPrompt`; the page wires it to a setter that pre-fills the
  drawer's input AND opens it in the same tick.
- `/insights` owns `coachOpen` + `coachPrefill` state. The drawer
  mounts with `key={prefill ?? "blank"}` so the lazy `useState`
  initialiser fires fresh on every chip transition, sidestepping
  the `react-hooks/set-state-in-effect` rule.

Tests:
- Updates the hero-strip ratchet to allow either disabled (no
  handler) or enabled (handler supplied) states.
- Adds three guards under `insights-polish.test.ts` that pin the
  page-side wiring (CoachDrawer import, hero handler hook-up,
  state ownership).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/insights/__tests__/hero-strip.test.tsx

@@ -124,11 +124,30 @@ describe("<HeroStrip>", () => {
     );
   });
 
-  it("renders the ask-the-coach action button as disabled with a 'Coming soon' title", () => {
+  it("renders the ask-the-coach action button as disabled with a 'Coming soon' title when no handler is supplied", () => {
     const html = render(<HeroStrip briefing={null} now={morningLocal} />);
-    expect(html).toMatch(
-      /data-slot="insights-hero-strip-action-coach"[^>]*disabled[^>]*title="Coming soon"/,
+    const coachTag = html.match(
+      /<button[^>]*data-slot="insights-hero-strip-action-coach"[^>]*>/,
     );
+    expect(coachTag).not.toBeNull();
+    expect(coachTag?.[0]).toMatch(/\sdisabled(=""|\s|>)/);
+    expect(coachTag?.[0]).toContain('title="Coming soon"');
+  });
+
+  it("enables the ask-the-coach button when onAskCoach is supplied (B2b)", () => {
+    const html = render(
+      <HeroStrip
+        briefing={null}
+        now={morningLocal}
+        onAskCoach={() => {}}
+      />,
+    );
+    const coachTag = html.match(
+      /<button[^>]*data-slot="insights-hero-strip-action-coach"[^>]*>/,
+    );
+    expect(coachTag).not.toBeNull();
+    expect(coachTag?.[0]).not.toMatch(/\sdisabled(=""|\s|>)/);
+    expect(coachTag?.[0]).not.toContain('title="Coming soon"');
   });
 
   it("renders the regenerate button when onRegenerate is supplied", () => {

src/components/insights/hero-strip.tsx

@@ -53,10 +53,18 @@ interface HeroStripProps {
   /** Disables the regenerate button + flips its icon to a spinner. */
   regenerating?: boolean;
   /**
-   * Click handler for the suggested prompts. The Coach drawer (B2)
-   * will own the routing; for B1 the parent passes a no-op.
+   * Click handler for the suggested prompts. The Coach drawer (B2b)
+   * routes a chip click into the drawer's input; the parent owns the
+   * drawer state. When omitted the chip click is a no-op.
    */
   onPickPrompt?: (prompt: string) => void;
+  /**
+   * Click handler for the "Ask the coach" action button. When supplied,
+   * the button is enabled and the coming-soon tooltip drops; clicking
+   * opens the drawer (B2b). When omitted the button stays disabled —
+   * see the v1.4.20 phase B1 dispatch where the drawer was deferred.
+   */
+  onAskCoach?: () => void;
   /**
    * Now() override for tests so the greeting bucket is deterministic.
    * Defaults to `new Date()`. Production callers omit this.
@@ -108,6 +116,7 @@ export function HeroStrip({
   onRegenerate,
   regenerating = false,
   onPickPrompt,
+  onAskCoach,
   now,
 }: HeroStripProps) {
   const { t } = useTranslations();
@@ -185,13 +194,18 @@ export function HeroStrip({
             <FileText className="h-3.5 w-3.5" aria-hidden="true" />
             <span>{t("insights.heroActionWeeklyReport")}</span>
           </Button>
-          {/* B2 wires this into the Coach drawer. */}
+          {/* B2b wires this into the Coach drawer. The button is
+              enabled whenever the parent supplies an `onAskCoach`
+              handler; older parents that haven't adopted B2b yet
+              still get the disabled "Coming soon" affordance so the
+              hero doesn't break. */}
           <Button
             type="button"
             variant="outline"
             size="sm"
-            disabled
-            title={comingSoon}
+            onClick={onAskCoach}
+            disabled={!onAskCoach}
+            title={onAskCoach ? undefined : comingSoon}
             data-slot="insights-hero-strip-action-coach"
             className="gap-1.5"
           >
@@ -227,9 +241,10 @@ export function HeroStrip({
           className="border-border/50 border-t pt-4"
         >
           {/*
-           * TODO(B2): wire onPickPrompt into the Coach drawer so a
-           * chip click pre-fills the input + opens the drawer. For
-           * B1 the parent passes a no-op.
+           * v1.4.20 phase B2b — chip clicks open the Coach drawer
+           * with the localised prompt pre-filled in the composer.
+           * The parent owns drawer state so the chip strip stays
+           * presentational.
            */}
           <SuggestedPrompts
             onPick={onPickPrompt ?? (() => undefined)}