feat(symptoms): add person-defined symptoms and timestamped occurrences

A symptom of one's own ("aura", "headache") is a definition with an
encrypted name and an icon from the cycle custom-symptom allowlist; each
occurrence carries a time, a 0-10 intensity (the pain score's scale), an
optional encrypted note and an optional link to one of the record's open
illness episodes. Both ride the illness module: every route answers
illness.disabled when it is off.

- Migration 0369 (idempotent): symptom_definitions and symptom_events,
  intensity CHECK 0-10, episode link ON DELETE SET NULL.
- /api/symptoms/definitions{,/[id]} and /api/symptoms/events{,/[id]}:
  eight active definitions per record (a hidden one frees its slot,
  showing it again re-checks), hide or purge, events create/list/edit/
  delete, a new link must name an open episode of the same record
  (422 symptoms.episode.notOpen). Error group symptoms.*.
- Sharing: reads at READ, logging an occurrence at WRITE, defining and
  editing at MANAGE; C1/C3/C4 audit details; frozen lists, the handler
  matrix and the activity verbs updated.
- Both encrypted columns registered and rotated; both models in the wipe
  plan; both carried at both backup ends with occurrences nested in their
  definition, plaintext in a portable file and ciphertext in a recovery
  file, and a link to an episode the file lacks dropped and named
  (symptomEpisodeReference).
- OpenAPI regenerated.

scripts/rotate-encryption-key.ts

@@ -594,6 +594,21 @@ async function main() {
       prisma.illnessDayLog,
     ),
   );
+  // v1.40 — person-defined symptoms: the name and the per-occurrence note.
+  results.push(
+    await rotateBytesColumn(
+      "SymptomDefinition",
+      "labelEncrypted",
+      prisma.symptomDefinition,
+    ),
+  );
+  results.push(
+    await rotateBytesColumn(
+      "SymptomEvent",
+      "noteEncrypted",
+      prisma.symptomEvent,
+    ),
+  );
 
   // ───── v1.19.0 ECG waveform (Bytes column) ─────
   // "waveformEncrypted" holds the JSON-encoded micro-volt sample array in the