feat(vaccinations): publish the routes, classify them, gate the module

- four route files: list and create, read and edit and delete, restore,
  and the link pair; every delegable one is classified as health
  background, in each leg of the sharing guard, with its reason written
- link and unlink stay bare, consistent with the document and visit link
  routes; the three are revisited as one decision
- vaccinations becomes the nineteenth module key, default-on and
  surface-gated like medications: the data routes stay exempt so a
  restore keeps working and re-enabling finds every dose intact
- a delegate's dose entries get their own sentence in the owner's
  activity view rather than reading as a generic change

src/components/settings/modules-section.tsx

@@ -53,6 +53,7 @@ import {
   Pill,
   Smile,
   Sparkles,
+  Syringe,
   TestTube,
   Thermometer,
   type LucideIcon,
@@ -110,6 +111,8 @@ const MODULE_ICONS: Record<ModuleKey, LucideIcon> = {
   mentalHealth: Brain,
   // v1.28 — opt-in micronutrient-intake sync (Apple Health day totals).
   nutrients: Leaf,
+  // v1.38.0 — the immunization log.
+  vaccinations: Syringe,
 };
 
 export function ModulesSection() {