refactor(checkups): split the checkups section into form, card and postpone sheet

The checkups file held two components of about 620 lines each. Their
parts move to components/measurement-reminders/checkups/:

- reminder-form: the type groups, cadence presets, the form state and
  its mapping to and from a reminder (pure)
- reminder-form-sheet: the create / edit sheet and its cadence fields
- checkup-card: the card in both views, its menu, details, skip and
  snooze lines, next / last lines and action row
- postpone-sheet: the postpone chips and date, the honest skip and its
  confirmation, and the calendar-day offsets

vorsorge-section.tsx keeps the list, the value capture and the visit
filing. Markup and behaviour are unchanged; the guards name the modules
that now hold what they check.

src/__tests__/baselines/source-file-lines.json

@@ -1,7 +1,7 @@
 {
   "$comment": "Production files over 800 lines and their length. Maintained by src/__tests__/source-size-ratchet.test.ts.",
-  "count": 116,
-  "total": 134457,
+  "count": 115,
+  "total": 132921,
   "entries": {
     "app/api/dashboard/summary/route.ts": 1032,
     "app/api/documents/inbound/route.ts": 811,
@@ -23,7 +23,6 @@
     "components/insights/health-score-card.tsx": 1023,
     "components/insights/insights-tab-strip.tsx": 1086,
     "components/layout/sidebar-nav.tsx": 855,
-    "components/measurement-reminders/vorsorge-section.tsx": 1536,
     "components/measurements/measurement-form.tsx": 815,
     "components/medications/detail/medication-detail-tabs.tsx": 1160,
     "components/medications/medication-table.tsx": 853,

src/__tests__/baselines/source-function-lines.json

@@ -1,7 +1,7 @@
 {
   "$comment": "Production functions over 200 lines, keyed \"file :: name\", and their length. Maintained by src/__tests__/source-size-ratchet.test.ts.",
-  "count": 402,
-  "total": 138967,
+  "count": 401,
+  "total": 138066,
   "entries": {
     "app/achievements/page.tsx :: AchievementsPage": 206,
     "app/api/admin/backups/upload/route.ts :: apiHandler(arg)": 314,
@@ -177,8 +177,7 @@
     "components/layout/top-bar.tsx :: TopBar": 212,
     "components/links/entity-link-picker.tsx :: EntityLinkPicker": 392,
     "components/measurement-reminders/vorsorge-dashboard-card.tsx :: VorsorgeDashboardCard": 215,
-    "components/measurement-reminders/vorsorge-section.tsx :: VorsorgeCard": 635,
-    "components/measurement-reminders/vorsorge-section.tsx :: VorsorgeSection": 618,
+    "components/measurement-reminders/vorsorge-section.tsx :: VorsorgeSection": 352,
     "components/measurements/measurement-form.tsx :: MeasurementForm": 500,
     "components/medications/detail/efficacy/efficacy-chart.tsx :: EfficacyChart": 361,
     "components/medications/detail/medication-detail-tabs.tsx :: MedicationDetailTabs": 771,

src/__tests__/baselines/version-stamp-comments.json

@@ -1,7 +1,7 @@
 {
   "$comment": "Comment lines that open with a release version, per file under src/. Maintained by src/__tests__/version-stamp-ratchet.test.ts.",
-  "count": 2948,
-  "total": 10257,
+  "count": 2947,
+  "total": 10231,
   "entries": {
     "__tests__/account-payload-consumer-guard.test.ts": 2,
     "__tests__/acting-account-boundary-guard.test.ts": 7,
@@ -1120,7 +1120,6 @@
     "components/layout/top-bar.tsx": 4,
     "components/measurement-reminders/__tests__/vorsorge-section.test.tsx": 7,
     "components/measurement-reminders/vorsorge-dashboard-card.tsx": 2,
-    "components/measurement-reminders/vorsorge-section.tsx": 26,
     "components/measurement-reminders/vorsorge-settings.tsx": 2,
     "components/measurements/__tests__/measurement-form-unit-label.test.tsx": 1,
     "components/measurements/__tests__/measurement-list-apple-health-badge.test.tsx": 4,

src/__tests__/date-order-explicit-formatter-guard.test.ts

@@ -260,7 +260,7 @@ const RAW_ALLOWLIST: ReadonlyArray<{ file: string; why: string }> = [
     why: "`makeDayKeyFormatter` — the per-row bucketing key. Its fields are read back through `formatToParts` and reassembled as `YYYY-MM-DD`.",
   },
   {
-    file: "src/components/measurement-reminders/vorsorge-section.tsx",
+    file: "src/components/measurement-reminders/checkups/postpone-sheet.tsx",
     why: "The ISO day the postpone request writes to the API. A wire value, and the wire format is ISO whatever the reader prefers.",
   },
   {

src/__tests__/destructive-control-guard.test.ts

@@ -448,7 +448,10 @@ const REGISTRY: DestructiveEntry[] = [
   {
     file: "hooks/use-measurement-reminders.ts",
     destroys: "a checkup or measurement reminder with its schedule",
-    triggers: ["components/measurement-reminders/vorsorge-section.tsx"],
+    triggers: [
+      "components/measurement-reminders/vorsorge-section.tsx",
+      "components/measurement-reminders/checkups/checkup-card.tsx",
+    ],
     recovery: "tombstoned-no-restore",
     confirm: ["AlertDialog"],
   },

src/__tests__/success-affordance-guard.test.ts

@@ -233,7 +233,7 @@ const PINNED_AFFORDANCES: Record<
   "src/components/measurement-reminders/vorsorge-dashboard-card.tsx": {
     CheckCircle2: 2,
   },
-  "src/components/measurement-reminders/vorsorge-section.tsx": {
+  "src/components/measurement-reminders/checkups/checkup-card.tsx": {
     CheckCircle2: 2,
     "text-success": 1,
   },

src/__tests__/vorsorge-due-bucket-single-home-guard.test.ts

@@ -36,7 +36,7 @@ const HOME_IMPORT = 'from "@/lib/measurement-reminders/due-day"';
  * shared body, that is the regression, not a reason to relax the test.
  */
 const RENDERING_SURFACES = [
-  "components/measurement-reminders/vorsorge-section.tsx",
+  "components/measurement-reminders/checkups/checkup-card.tsx",
   "components/measurement-reminders/vorsorge-dashboard-card.tsx",
 ];