feat(dashboard): show the VO2max tile by default when data exists

The VO2max strip tile was opt-in, so accounts that already sync a
cardio-fitness sample from Withings, Apple Health, Fitbit, or Oura saw
nothing on the dashboard. Default the strip tile on; it still self-gates
on having a VO2_MAX sample, so empty accounts keep a clean tile strip.
The chart row stays off — VO2max charts live on /insights/cardio-fitness.

src/lib/__tests__/dashboard-layout.test.ts

@@ -154,6 +154,21 @@ describe("DEFAULT_DASHBOARD_LAYOUT contract", () => {
     expect(widget?.tileVisible).toBe(true);
   });
 
+  it("ships the vo2Max strip tile default-on, chart row default-off (v1.18.9)", () => {
+    // VO2max is ingested from Withings / Apple Health / Fitbit / Oura but
+    // the tile used to be opt-in, so accounts that already synced a sample
+    // saw nothing on the dashboard. The strip tile is now on by default
+    // (it still self-gates on having a VO2_MAX sample in page.tsx), while
+    // the chart row stays off because VO2max charts live on the
+    // /insights/cardio-fitness sub-page.
+    const widget = DEFAULT_DASHBOARD_LAYOUT.widgets.find(
+      (w) => w.id === "vo2Max",
+    );
+    expect(widget).toBeDefined();
+    expect(widget?.tileVisible).toBe(true);
+    expect(widget?.visible).toBe(false);
+  });
+
   it("does NOT advertise a retired insightsPreview widget (v1.4.27 B1)", () => {
     // v1.4.27 B1 retired the standalone dashboard preview because it
     // duplicated the much-richer `/insights` advisor surface. The

src/lib/dashboard-layout.ts

@@ -29,11 +29,12 @@ export const DASHBOARD_WIDGET_IDS = [
   "bpInTarget",
   "oxygenSaturation",
   "achievements",
-  // v1.4.25 W8d — VO2 max trend tile (opt-in, secondary-metric pattern).
-  // Self-gates on having any VO2_MAX sample; default-invisible so
-  // existing dashboards stay unchanged until the user enables it in
-  // Settings → Dashboard. Only the tile-strip surface; chart row
-  // lands alongside the iOS-app body-composition sub-page in v1.5.
+  // v1.4.25 W8d — VO2 max trend tile (secondary-metric pattern). The
+  // strip tile is on by default and self-gates on having any VO2_MAX
+  // sample, so accounts that sync cardio fitness see it without enabling
+  // it in Settings → Dashboard, while empty accounts get a clean tile
+  // strip. Only the tile-strip surface; the chart row lives on the
+  // /insights/cardio-fitness sub-page.
   "vo2Max",
   // v1.4.32 — "Recent workouts" tile. Surfaces the three most-recent
   // canonical workouts; self-gates on at least one row. Default-on
@@ -379,11 +380,14 @@ export const DEFAULT_DASHBOARD_LAYOUT: DashboardLayout = {
     // `tileVisible` is forced false because there is no tile surface
     // for this widget; only the chart-row card.
     { id: "achievements", visible: true, tileVisible: false, order: 13 },
-    // v1.4.25 W8d — VO2 max trend tile. Default-invisible on both
-    // surfaces; opt-in via Settings → Dashboard. Only the tile-strip
-    // representation today (`visible` stays false so the chart-row
-    // gate never fires; the chart card lands in v1.5).
-    { id: "vo2Max", visible: false, tileVisible: false, order: 14 },
+    // v1.4.25 W8d — VO2 max trend tile. The strip tile is on by default
+    // (`tileVisible: true`) so accounts that already sync a VO2max sample
+    // see cardio fitness without hunting through Settings → Dashboard; the
+    // tile self-gates on having any VO2_MAX sample (see `showVo2Tile` in
+    // page.tsx), so accounts with no sample still get a clean dashboard.
+    // The chart row stays off (`visible: false`) — VO2max charts live on
+    // the /insights/cardio-fitness and /insights/pulse sub-pages.
+    { id: "vo2Max", visible: false, tileVisible: true, order: 14 },
     // v1.4.32 — Recent workouts dashboard tile. Default-visible so
     // brand-new accounts discover the workout surface without
     // hunting through Settings; the tile self-gates on a non-empty