refactor(backup): run the restore as ordered steps from per-domain modules

restoreBackup becomes an orchestrator: the checks before the first delete
move to restore-preflight.ts, and the transaction runs the steps listed in
backup-domains.ts in dependency order, emptying the account first and then
rebuilding it domain by domain. The inline restores for measurements,
medications, mood, labs, illness, allergies, family history, workouts,
nutrient days, documents, the instance settings and the cleared
notification channels move into one module per domain, beside the
existing section modules. Cross-domain references travel through one
typed context instead of local variables.

The order of every write, the refusals and their audit rows, the skip
report, the cleared counts and the reported phases are unchanged; the
golden copies of the restored account still match. Guards that pinned
the restore by path now point at the domain files.

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

@@ -1,7 +1,7 @@
 {
   "$comment": "Production functions over 200 lines, keyed \"file :: name\", and their length. Maintained by src/__tests__/source-size-ratchet.test.ts.",
-  "count": 415,
-  "total": 154643,
+  "count": 413,
+  "total": 149647,
   "entries": {
     "app/achievements/page.tsx :: AchievementsPage": 206,
     "app/api/admin/backups/upload/route.ts :: apiHandler(arg)": 314,
@@ -324,8 +324,6 @@
     "lib/export/profile-backup.ts :: buildProfileBackupSection": 270,
     "lib/export/profile-backup.ts :: restoreProfileData": 291,
     "lib/export/records-backup.ts :: buildRecordsBackupSection": 308,
-    "lib/export/restore-backup.ts :: restoreBackup": 2833,
-    "lib/export/restore-backup.ts :: restoreBackup > prisma.$transaction(arg)": 2163,
     "lib/export/vaccinations-backup.ts :: restoreVaccinationsData": 216,
     "lib/export/visits-backup.ts :: restoreVisitsData": 261,
     "lib/fhir/build-bundle.ts :: buildFhirDocumentBundle": 363,