feat: rework EOL, repairs, and hosts for real workflow

Four domain-model changes driven by exercising the deployed 2.0 build:

- EOL moves from manufacturer to MPN via new PartModel catalog table,
  so alerts fire on the thing that actually ages.
- Repairs re-home to Host (required hostId + problem text) with an
  optional RepairJobPart join for affected parts; drop Part.replacementPartId.
- New /repairs/:id detail page with editable problem, part list, and
  a RepairComment thread (REPAIR_COMMENTED events fan out to each
  problem part's timeline).
- Host.assetId (required, unique) surfaces prominently on the repair
  page so techs can confirm they're touching the right box.

Single destructive migration reshapes existing dev data. All 7 packages
typecheck clean; 30 API tests pass (9 new covering host membership,
upsertByMpn idempotency + race, assetId 409, comment userId stamping).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packages/shared/src/enums.ts

@@ -13,6 +13,8 @@ export const PartEventType = z.enum([
   'FIELD_UPDATED',
   'REPAIR_STARTED',
   'REPAIR_COMPLETED',
+  'REPAIR_CANCELLED',
+  'REPAIR_COMMENTED',
   'TAG_ADDED',
   'TAG_REMOVED',
 ]);