fix(copy): make delete confirmations, sleep-debt labels, and the glucose band honest

Three surfaces where the words no longer matched the code, plus the missing
web control for a preference the server already honours.

Delete confirmations. Four dialogs promised permanence on surfaces that
render an Undo: the measurements and mood bulk bodies, the lab-result body,
and the illness-episode body (which said "cannot be undone" sixty lines
below the code that fires the Undo toast). All four now use the same
sentence the single-row measurement and mood dialogs already used. A sweep
of every other confirmation in the tree found the rest accurate — the
biomarker cascade, the mood-tag purge, and the account purge keep their
warning because those deletes really are unrecoverable.

Sleep debt. v1.19.0 replaced the summed shortfall with a running balance
that credits catch-up sleep; the labels still described the old sum, so the
word contradicted the number for anyone who slept in after a short night.
Corrected in all six locales, plus the places the old semantics had
propagated: the Coach system prompt, the OpenAPI field descriptions the
native client reads, and four module docblocks.

Glucose reference band. `hasDiabetes` selects the tighter reference band and
grounds the Coach, but no web surface set it — a web-only account was pinned
to the non-diabetic scale with no way out. The control goes on Targets,
above the per-metric editor, because it answers the same question that page
answers and the two are ordered: it picks the default band, an override
below beats it. The copy says what it is — a reference band, not a
diagnosis, never inferred from a reading, no clinical action taken on it.

The passkey list was reported as always reading "never used". It does not
reproduce: the column is selected by the list route and stamped on every
verified assertion, both since v1.23.0. Pinned with tests on both halves so
the contract cannot quietly regress.

src/lib/ai/coach/__tests__/system-prompt.test.ts

@@ -202,7 +202,7 @@ describe("getCoachSystemPrompt — DE", () => {
     // German coach can cite glucose + duration values with a valid token.
     expect(prompt).toMatch(/mg\/dL/);
     expect(prompt).toMatch(/mmol\/L/);
-    expect(prompt).toMatch(/min[\s\S]*\(Schlafdefizit/);
+    expect(prompt).toMatch(/min[\s\S]*\(Schlafschuld/);
   });
 
   it("carries the v1.21.2 narrative-presence clauses (A4/A5/A6/A7)", () => {

src/lib/ai/coach/snapshot-blocks/sleep-block.ts

@@ -157,7 +157,7 @@ interface SleepRhythmBlockContext {
  * ── v1.17.0 sleep-rhythm block (sleep-debt + chronotype) ──────────
  *
  * The two server-authoritative timing signals the Sleep page + the
- * dashboard summary render — cumulative sleep debt and the MCTQ
+ * dashboard summary render — the outstanding sleep-debt balance and the MCTQ
  * chronotype band + social jetlag. Built from the SAME assembler the
  * dashboard route uses (`reconstructNights` → `computeSleepRhythmFromNights`),
  * over the rhythm's OWN fixed trailing-42-day rows, so the coach quotes the

src/lib/ai/coach/system-prompt.ts

@@ -361,8 +361,9 @@ ISO-week means.
   timing signals — the SAME values the Sleep page and dashboard show, so
   cite them as the user sees them and never recompute. It holds:
   - "sleepDebt": { state, debtMinutes, needMinutes }. "debtMinutes" is
-    the cumulative deficit against the age-based nightly need over the
-    trailing window, "needMinutes" the target per night — both in
+    the OUTSTANDING BALANCE against the age-based nightly need over the
+    trailing window — a short night adds to it, a long night pays it
+    down, and it floors at 0 — "needMinutes" the target per night — both in
     MINUTES (convert to hours/minutes when you speak, e.g. 320 → "5h
     20m of sleep debt"). When "state" is "partial" the window is still
     short: treat the figure as still calibrating, not a firm number.
@@ -980,7 +981,7 @@ Regeln:
 - "value" ist ein vorformatierter Anzeigestring ("138/85", "84,2",
   "4,1"). Stimmung als N/5 formatieren, wenn numerisch.
 - "unit" ist eines aus mmHg, kg, bpm, /5, %, mg/dL, mmol/L, min
-  (Schlafdefizit / sozialer Jetlag).
+  (Schlafschuld / sozialer Jetlag).
 - "window" ist eines aus last7days, last30days, last90days, allTime;
   bei Tages-Pins weglassen.
 - Lass den ganzen Block weg (KEINE ---KEYVALUES---Zeile, KEINE

src/lib/auth/__tests__/passkey.test.ts

@@ -137,3 +137,43 @@ describe("verifyAuthentication — Zod boundary (L-3)", () => {
     expect(out.verification.verified).toBe(true);
   });
 });
+
+/**
+ * "Last used" is a security-page fact people act on: a passkey that reads
+ * "never used" invites deletion. The column is only ever written here, on a
+ * verified assertion, so the stamp and the counter bump must stay one write.
+ * The read half is pinned in
+ * `src/app/api/auth/passkeys/__tests__/route.test.ts`.
+ */
+describe("verifyAuthentication — last-used stamp", () => {
+  // The file-level `beforeEach` re-arms the mocks but does not clear their
+  // call history, so the write assertions below need a clean ledger.
+  beforeEach(() => {
+    vi.mocked(prisma.passkey.update).mockClear();
+  });
+
+  it("stamps lastUsedAt alongside the counter on a verified assertion", async () => {
+    const before = Date.now();
+    await verifyAuthentication("ch-1", VALID_BODY);
+
+    expect(prisma.passkey.update).toHaveBeenCalledTimes(1);
+    const call = vi.mocked(prisma.passkey.update).mock.calls[0][0];
+
+    expect(call.where).toEqual({ id: "pk-1" });
+    expect(call.data?.counter).toBe(BigInt(1));
+
+    const stamped = call.data?.lastUsedAt;
+    expect(stamped).toBeInstanceOf(Date);
+    expect((stamped as Date).getTime()).toBeGreaterThanOrEqual(before);
+  });
+
+  it("does not stamp lastUsedAt when the assertion fails", async () => {
+    vi.mocked(verifyAuthenticationResponse).mockResolvedValue({
+      verified: false,
+    } as never);
+
+    await verifyAuthentication("ch-1", VALID_BODY);
+
+    expect(prisma.passkey.update).not.toHaveBeenCalled();
+  });
+});

src/lib/insights/derived/sleep-rhythm.ts

@@ -4,7 +4,8 @@
  * The one place that turns a user's raw `SLEEP_DURATION` rows into the two
  * timing signals the Sleep page + the iOS client + the dashboard render:
  *
- *   - cumulative SLEEP DEBT over the rolling window (`computeSleepDebt`), and
+ *   - the outstanding SLEEP DEBT balance over the rolling window
+ *     (`computeSleepDebt`; surplus sleep pays it down), and
  *   - MCTQ CHRONOTYPE + social jetlag (`computeChronotype`).
  *
  * ONE ENGINE, NO DUPLICATION

src/lib/openapi/routes/measurements.ts

@@ -417,13 +417,15 @@ const sleepDebtResource = z.object({
   state: z
     .enum(["partial", "ready"])
     .describe(
-      "`partial` until enough tracked nights exist (calm 'still learning'); `ready` once the rolling window can assert a cumulative debt.",
+      "`partial` until enough tracked nights exist (calm 'still learning'); `ready` once the rolling window can assert a balance.",
     ),
   debtMinutes: z
     .number()
     .int()
     .nonnegative()
-    .describe("Cumulative sleep debt over the window, in minutes, after caps."),
+    .describe(
+      "Outstanding sleep-debt balance over the window, in minutes, after caps. A night below need adds its shortfall; a night above need pays the balance down (floored at 0).",
+    ),
   needMinutes: z
     .number()
     .int()
@@ -513,7 +515,7 @@ const sleepRhythmResponse = z
   .meta({
     id: "SleepRhythmResource",
     description:
-      "Server-authoritative sleep-rhythm read: cumulative sleep debt over the rolling window + MCTQ chronotype (MSF/MSFsc band, social jetlag). Free vs work nights default to weekend = free in the user's timezone (no work calendar). A view over existing per-stage SLEEP_DURATION rows — no schema, no new type.",
+      "Server-authoritative sleep-rhythm read: the outstanding sleep-debt balance over the rolling window + MCTQ chronotype (MSF/MSFsc band, social jetlag). Free vs work nights default to weekend = free in the user's timezone (no work calendar). A view over existing per-stage SLEEP_DURATION rows — no schema, no new type.",
   });
 
 // ── Time-series adapter (iOS chart source) ───────────────────────────
@@ -1004,7 +1006,7 @@ export const measurementPaths: NonNullable<ZodOpenApiObject["paths"]> = {
       tags: ["Measurements"],
       summary: "Sleep rhythm — sleep-debt + chronotype (v1.17.0)",
       description:
-        "Returns the two server-authoritative sleep-timing signals the Sleep page + iOS render off the same canonical night reconstruction the Sleep Score uses: cumulative `sleepDebt` over the rolling window (calm `partial` state under the night threshold) and MCTQ `chronotype` (MSF/MSFsc band + social jetlag, `learning` state until enough free-day nights exist). Free vs work nights default to weekend = free in the user's timezone (no work calendar). A read-only view over existing per-stage SLEEP_DURATION rows — no schema, no new measurement type.",
+        "Returns the two server-authoritative sleep-timing signals the Sleep page + iOS render off the same canonical night reconstruction the Sleep Score uses: the outstanding `sleepDebt` balance over the rolling window (calm `partial` state under the night threshold) and MCTQ `chronotype` (MSF/MSFsc band + social jetlag, `learning` state until enough free-day nights exist). Free vs work nights default to weekend = free in the user's timezone (no work calendar). A read-only view over existing per-stage SLEEP_DURATION rows — no schema, no new measurement type.",
       responses: {
         "200": {
           description: "Sleep-debt + chronotype DTO.",

src/lib/query-keys/settings.ts

@@ -21,6 +21,14 @@ export const settingsKeys = {
   /** v1.8.5 — user-level injection-site preferences (global exclusion). */
   injectionSitePrefs: () => ["settings", "injection-site-prefs"] as const,
 
+  /**
+   * The declared diabetes opt-in behind `GET/PATCH /api/auth/me/diabetes`.
+   * Selects which reference band glucose readings are judged against, so the
+   * toggle also invalidates `insightsTargets()` — the resolved band rides
+   * on that payload.
+   */
+  diabetesPref: () => ["settings", "diabetes"] as const,
+
   /**
    * v1.18.0 — the per-user module enable/disable map behind
    * `GET/PATCH /api/auth/me/modules`. Used as the Module-hub mutation key;