feat(illness): add the condition-journal MVP behind a born-gated module

Introduce a retrospective illness/condition journal: episodes with a
lifecycle (acute / chronic-ongoing / recurring / flare) and a daily
symptom timeline forked structurally from the cycle log-day surface. The
journal is a record, not a medical device — no prediction or diagnosis UI.

- Register `illness` as a born-gated (opt-in / default-off) module. The
  gate resolver flips the disabled-allowlist default to off for born-gated
  keys, so the surface stays dark until the account opts in from the
  Modules hub. `isIllnessEnabled` + `requireIllnessEnabled` delegate to the
  module foundation (one source of truth) and re-stamp an illness errorCode.
- Episode CRUD under /api/illness: list / create / get / edit / resolve /
  delete, plus a per-episode-day day-log upsert on (episodeId, date). Every
  route wraps apiHandler, Zod-validates with returnAllZodIssues, narrows
  userId from auth, builds data field-by-field, and gates the module.
  Free-text notes encrypt at rest through the shared Bytes codec.
- Log-day sheet (cycle fork): ~8 Jackson/WURSS symptom chips 0-3 + a
  functional-impact group + fever + an encrypted note, one row per day.
- Episode history page + a born-gated nav entry, neutral palette, status
  via a neutral Badge, retrospective-only copy. i18n across all six locales.
- Cover the new routes in the module-route-gate inventory; unit tests for
  the day-log upsert, the gate enforcement, and the born-gated resolver.

The /api/auth/me module map now projects the `illness` flag (openapi.yaml
regenerated).

src/app/api/__tests__/module-route-gate-inventory.test.ts

@@ -75,6 +75,14 @@ const MODULE_ROUTE_TREES: ReadonlyArray<string> = [
   "src/app/api/workouts",
   "src/app/api/labs",
   "src/app/api/cycle",
+  // v1.18.1 (W-B) — the illness/condition journal. Every `/api/illness/*`
+  // route gates on the born-gated `illness` module via the thin
+  // `requireIllnessEnabled(...)` wrapper (which re-stamps the
+  // illness-specific errorCode over `requireModuleEnabled("illness")`),
+  // recognised below as a delegated gate. Walking the tree means a NEW
+  // ungated illness route fails this test BY NAME rather than leaking the
+  // surface over a Bearer token when the account never opted in.
+  "src/app/api/illness",
   "src/app/api/gamification",
   // v1.18.0 B3 — the legacy `/api/doctor-report` tree (JSON + server-PDF +
   // availability probe) was orphaned dead code (no production caller) and
@@ -168,6 +176,12 @@ const EXEMPT_ROUTES: ReadonlyArray<string> = [
 const MODULE_GATE_NEEDLE = "requireModuleEnabled(";
 const CYCLE_GATE_NEEDLE = "requireCycleEnabled(";
 const COACH_GATE_NEEDLE = 'requireAssistantSurface("coach")';
+// v1.18.1 — the illness journal's thin gate wrapper. `requireIllnessEnabled`
+// delegates to `requireModuleEnabled(userId, "illness")` and re-stamps the
+// illness-specific errorCode, exactly mirroring how `cycle` delegates to
+// `requireCycleEnabled`. Recognised as a delegated gate so illness routes
+// are not flagged as ungated.
+const ILLNESS_GATE_NEEDLE = "requireIllnessEnabled(";
 // Builder aggregators that resolve `resolveModuleMap` once and exclude
 // disabled-module sections/resources at the build boundary.
 const BUILDER_GATE_NEEDLES: ReadonlyArray<string> = [
@@ -251,6 +265,7 @@ describe("module API route gate inventory", () => {
       "workouts",
       "recovery",
       "labs",
+      "illness",
       "achievements",
       "cycle",
       "coach",
@@ -276,6 +291,7 @@ describe("module API route gate inventory", () => {
       if (fileHasCall(text, MODULE_GATE_NEEDLE)) continue;
       if (fileHasCall(text, CYCLE_GATE_NEEDLE)) continue;
       if (fileHasCall(text, COACH_GATE_NEEDLE)) continue;
+      if (fileHasCall(text, ILLNESS_GATE_NEEDLE)) continue;
       if (BUILDER_GATE_NEEDLES.some((n) => fileHasCall(text, n))) continue;
 
       if (exempt.has(path)) continue;
@@ -346,6 +362,7 @@ describe("module API route gate inventory", () => {
         fileHasCall(text, MODULE_GATE_NEEDLE) ||
         fileHasCall(text, CYCLE_GATE_NEEDLE) ||
         fileHasCall(text, COACH_GATE_NEEDLE) ||
+        fileHasCall(text, ILLNESS_GATE_NEEDLE) ||
         BUILDER_GATE_NEEDLES.some((n) => fileHasCall(text, n))
       ) {
         stillGated.push(path);