fix(dashboard): stop the widgets PUT discarding a comparison baseline

The layout PUT preserved chartOverlayPrefs, selectedScoreRings and
heroRingOrder when a client omitted them, but the top-level
comparisonBaseline was not in that merge. serializeDashboardLayout clamps
a missing baseline to "none", so a layout save from a client that does
not know the field — the native client treats it as web-only and never
sends it — silently reset the comparison the user had picked on the web.
No error, no audit row.

Replace the hand-maintained three-field merge with an explicit
disposition map over every top-level layout field. The map is declared
`satisfies Record<keyof DashboardLayout, ...>`, so adding a layout field
without deciding replace-or-preserve fails typecheck; the preserve set
and the merge are derived from it rather than restated. The stored-layout
read is skipped when the client sent the full set.

Also catalogue the four clinical signals the native client pins — grip
strength, pain NRS, waist circumference, waist-to-height. They reached
the route as unknown ids, were filtered out ahead of Zod, and vanished
from the persisted layout, so a tile placement was lost on every save.
They join the iOS-only set because the web dashboard has no render path
for them; their charts live on the insights sub-pages. Raise the widget
array cap to 50 to clear the now-42-id catalogue.

src/app/api/dashboard/widgets/__tests__/route.test.ts

@@ -517,3 +517,122 @@ describe("dashboard widgets — 27-id catalogue round-trip (v1.7.0 W1)", () => {
     );
   });
 });
+
+describe("dashboard widgets — preserve-when-absent on PUT", () => {
+  it("keeps the stored comparisonBaseline when the client omits it", async () => {
+    // The regression: a layout save from a client that doesn't know
+    // `comparisonBaseline` (the native client documents the field as
+    // web-only and never sends it) used to fall through to the serializer,
+    // which clamps a missing baseline to "none". The user's web-chosen
+    // comparison silently reset on every tile reorder from the phone.
+    const stored: DashboardLayout = serializeDashboardLayout({
+      version: 1,
+      widgets: [{ id: "weight", visible: true, tileVisible: true, order: 0 }],
+      comparisonBaseline: "lastYear",
+    });
+    vi.mocked(prisma.user.findUnique).mockResolvedValue({
+      dashboardWidgetsJson: stored,
+    } as never);
+    vi.mocked(prisma.user.update).mockResolvedValue({} as never);
+
+    const res = await callPut(
+      makeReq({
+        version: 1,
+        widgets: [
+          { id: "weight", visible: false, tileVisible: true, order: 0 },
+        ],
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    const updateArg = vi.mocked(prisma.user.update).mock
+      .calls[0]?.[0] as unknown as {
+      data: { dashboardWidgetsJson: { comparisonBaseline: string } };
+    };
+    expect(updateArg.data.dashboardWidgetsJson.comparisonBaseline).toBe(
+      "lastYear",
+    );
+
+    const body = (await res.json()) as {
+      data: { comparisonBaseline: string };
+    };
+    expect(body.data.comparisonBaseline).toBe("lastYear");
+  });
+
+  it("honours an explicitly sent comparisonBaseline over the stored one", async () => {
+    // Preserve-when-absent must not become preserve-always: the web
+    // CompareToggle sends the field, including an explicit "none" to clear.
+    const stored: DashboardLayout = serializeDashboardLayout({
+      version: 1,
+      widgets: [{ id: "weight", visible: true, tileVisible: true, order: 0 }],
+      comparisonBaseline: "lastYear",
+    });
+    vi.mocked(prisma.user.findUnique).mockResolvedValue({
+      dashboardWidgetsJson: stored,
+    } as never);
+    vi.mocked(prisma.user.update).mockResolvedValue({} as never);
+
+    const res = await callPut(
+      makeReq({
+        version: 1,
+        widgets: [{ id: "weight", visible: true, tileVisible: true, order: 0 }],
+        comparisonBaseline: "none",
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    const updateArg = vi.mocked(prisma.user.update).mock
+      .calls[0]?.[0] as unknown as {
+      data: { dashboardWidgetsJson: { comparisonBaseline: string } };
+    };
+    expect(updateArg.data.dashboardWidgetsJson.comparisonBaseline).toBe("none");
+  });
+
+  it("persists the four clinical tiles the native client pins", async () => {
+    // They used to hit the unknown-id filter ahead of Zod and vanish from
+    // the persisted layout, so the placement was lost on every save.
+    vi.mocked(prisma.user.findUnique).mockResolvedValue({
+      dashboardWidgetsJson: null,
+    } as never);
+    vi.mocked(prisma.user.update).mockResolvedValue({} as never);
+
+    const clinicalIds = [
+      "gripStrength",
+      "painNRS",
+      "waistCircumference",
+      "waistToHeight",
+    ];
+    const res = await callPut(
+      makeReq({
+        version: 1,
+        widgets: clinicalIds.map((id, i) => ({
+          id,
+          visible: true,
+          tileVisible: true,
+          order: i,
+        })),
+      }),
+    );
+    expect(res.status).toBe(200);
+
+    const dropAnnotate = vi
+      .mocked(annotate)
+      .mock.calls.find(
+        (c) =>
+          (c[0] as { action?: { name?: string } }).action?.name ===
+          "dashboard.widgets.unknown-id-dropped",
+      );
+    expect(dropAnnotate).toBeUndefined();
+
+    const updateArg = vi.mocked(prisma.user.update).mock
+      .calls[0]?.[0] as unknown as {
+      data: { dashboardWidgetsJson: { widgets: Array<{ id: string }> } };
+    };
+    const persistedIds = updateArg.data.dashboardWidgetsJson.widgets.map(
+      (w) => w.id,
+    );
+    for (const id of clinicalIds) {
+      expect(persistedIds).toContain(id);
+    }
+  });
+});

src/app/api/dashboard/widgets/route.ts

@@ -26,10 +26,9 @@ import {
   MAX_SELECTED_SCORE_RINGS,
   HERO_RING_IDS,
   MAX_HERO_RING_ORDER,
-  type ChartOverlayPrefsMap,
+  layoutNeedsPreserveRead,
+  mergePreservedLayoutFields,
   type DashboardLayout,
-  type ScoreRingId,
-  type HeroRingId,
 } from "@/lib/dashboard-layout";
 import { Prisma } from "@/generated/prisma/client";
 import { z } from "zod/v4";
@@ -80,7 +79,12 @@ const layoutSchema = z.object({
     // 11 iOS-only = 35) fits with headroom after the v1.10 additive
     // HealthKit signals became pinnable; the enum still bounds each id to
     // one of the catalogue ids.
-    .max(40),
+    //
+    // Raised again to 50 when the four clinical signals joined the
+    // catalogue (42 ids). The cap only has to clear the catalogue size —
+    // the enum bounds each entry and the id set is closed — so it carries
+    // headroom rather than tracking the count exactly.
+    .max(50),
   // v1.4.16 phase B8 — comparison baseline (Vormonat / Vorjahr) rides
   // on the layout blob per research §7 Q3 (no Prisma migration). Optional
   // so v1.4.15 clients that don't know the field can still PUT.
@@ -274,24 +278,27 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     return returnAllZodIssues(parsed.error, 422);
   }
 
-  // v1.4.18 — preserve any per-chart overlay prefs that the client
-  // didn't send. The dashboard-layout PUT typically saves widget
-  // visibility / order; chart prefs are PUT through their own route
-  // (`/api/dashboard/chart-overlay-prefs`) and would otherwise be
-  // wiped here on a subsequent layout save. `selectedScoreRings` and
-  // `heroRingOrder` ride the same preserve-when-absent contract — an
-  // older client's layout save must not reset either choice. One
-  // stored-layout read covers all fallbacks.
-  let mergedChartOverlayPrefs: ChartOverlayPrefsMap | undefined = parsed.data
-    .chartOverlayPrefs as ChartOverlayPrefsMap | undefined;
-  let mergedScoreRings: ScoreRingId[] | undefined =
-    parsed.data.selectedScoreRings;
-  let mergedHeroRingOrder: HeroRingId[] | undefined = parsed.data.heroRingOrder;
-  if (
-    mergedChartOverlayPrefs === undefined ||
-    mergedScoreRings === undefined ||
-    mergedHeroRingOrder === undefined
-  ) {
+  // Preserve-when-absent: every field the client didn't send is carried
+  // forward from the stored layout rather than clamped to its default by
+  // the serializer. The dashboard-layout PUT typically saves widget
+  // visibility / order, while chart prefs are PUT through their own route
+  // (`/api/dashboard/chart-overlay-prefs`), the hero rings come from
+  // Settings, and `comparisonBaseline` is web-only — an omission from any
+  // one surface must not reset a choice made on another.
+  //
+  // The preserve set is not a list maintained here: it is derived from
+  // `LAYOUT_FIELD_MERGE_DISPOSITION`, which the type system forces to cover
+  // every field of `DashboardLayout`. Adding a layout field without a
+  // disposition fails typecheck, so the next field cannot silently miss this
+  // merge the way `comparisonBaseline` did. One stored-layout read covers
+  // every fallback, and the read is skipped entirely when the client sent
+  // the full set.
+  // The Zod shape leaves the per-chart `comparisonBaseline` optional while
+  // `ChartOverlayPrefs` requires it; `coerceChartOverlayPrefsMap` inside the
+  // serializer fills the gap, so the assertion is safe here exactly as it was
+  // on the previous per-field cast.
+  let toSerialize = parsed.data as Partial<DashboardLayout>;
+  if (layoutNeedsPreserveRead(toSerialize)) {
     const existing = await prisma.user.findUnique({
       where: { id: user.id },
       select: { dashboardWidgetsJson: true },
@@ -299,22 +306,9 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     const existingLayout = resolveDashboardLayout(
       existing?.dashboardWidgetsJson,
     );
-    if (mergedChartOverlayPrefs === undefined) {
-      mergedChartOverlayPrefs = existingLayout.chartOverlayPrefs ?? {};
-    }
-    if (mergedScoreRings === undefined) {
-      mergedScoreRings = existingLayout.selectedScoreRings;
-    }
-    if (mergedHeroRingOrder === undefined) {
-      mergedHeroRingOrder = existingLayout.heroRingOrder;
-    }
+    toSerialize = mergePreservedLayoutFields(toSerialize, existingLayout);
   }
-  const normalized = serializeDashboardLayout({
-    ...parsed.data,
-    chartOverlayPrefs: mergedChartOverlayPrefs,
-    selectedScoreRings: mergedScoreRings,
-    heroRingOrder: mergedHeroRingOrder,
-  } as DashboardLayout);
+  const normalized = serializeDashboardLayout(toSerialize as DashboardLayout);
 
   await prisma.user.update({
     where: { id: user.id },