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.

src/components/admin/backups-section.tsx

@@ -461,6 +461,9 @@ function catalogueLabel(
   if (catalogue === "ecgReference") {
     return t("admin.section.backups.restoreSkippedEcgReference");
   }
+  if (catalogue === "symptomEpisodeReference") {
+    return t("admin.section.backups.restoreSkippedSymptomEpisodeReference");
+  }
   if (catalogue === "medicationTarget") {
     return t("admin.section.backups.restoreSkippedMedicationTarget");
   }