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>

apps/web/src/App.tsx

@@ -12,7 +12,9 @@ import Parts from './pages/Parts.js';
 import PartDetail from './pages/PartDetail.js';
 import Locations from './pages/Locations.js';
 import Manufacturers from './pages/Manufacturers.js';
+import PartModels from './pages/PartModels.js';
 import Repairs from './pages/Repairs.js';
+import RepairDetail from './pages/RepairDetail.js';
 import Hosts from './pages/Hosts.js';
 import Users from './pages/admin/Users.js';
 import Webhooks from './pages/admin/Webhooks.js';
@@ -54,7 +56,9 @@ export default function App() {
                     <Route path="/parts/:id" element={<PartDetail />} />
                     <Route path="/locations" element={<Locations />} />
                     <Route path="/manufacturers" element={<Manufacturers />} />
+                    <Route path="/part-models" element={<PartModels />} />
                     <Route path="/repairs" element={<Repairs />} />
+                    <Route path="/repairs/:id" element={<RepairDetail />} />
                     <Route path="/hosts" element={<Hosts />} />
                     <Route
                       path="/admin/users"