feat: split Repairs into FM, Repair, and Custody workflows

The old Repairs module had grown ticketing-system features (status lifecycle,
comments, assignee, notes) that duplicate what the external ticketing tool
already owns. Vector only needs to track whether maintenance is open or closed.

- Rename RepairJob -> Fm (OPEN/CLOSED only), drop RepairComment, assignee, notes
- New Repair table: persistent log of physical part swaps, with ingest on
  unknown broken MPN via partModels.upsertByMpn
- New custody model: PENDING_DROP_IN_CUSTODY / PENDING_DESTRUCTION_IN_CUSTODY
  states + Part.custodianId, with a "My Custody" page for drop-off
- PartModel.destroyOnFail routes broken parts to the destruction path
- Host lookup on /fms and /repairs accepts hostId XOR assetId
- Wire the dormant webhook emitter: fm.opened, fm.closed, repair.logged
- Single fresh Prisma migration (dev DB was wiped, no backfill)

Tests: 60 passing (custody transitions in parts.test.ts; new fms.test.ts,
repairs.test.ts, custody.test.ts covering happy paths, validation failures,
webhook emissions, and ingest-on-unknown-MPN).

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

apps/web/src/components/layout/Sidebar.tsx

@@ -1,8 +1,10 @@
 import { NavLink } from 'react-router-dom';
 import {
+  ArrowRightLeft,
   Boxes,
   ChevronsLeft,
   ChevronsRight,
+  Hand,
   LayoutDashboard,
   Layers,
   type LucideIcon,
@@ -29,7 +31,9 @@ const NAV_ITEMS: NavItem[] = [
   { to: '/part-models', label: 'Part models', icon: Layers },
   { to: '/locations', label: 'Locations', icon: MapPinned },
   { to: '/manufacturers', label: 'Manufacturers', icon: Boxes },
-  { to: '/repairs', label: 'Repairs', icon: Wrench },
+  { to: '/fms', label: 'FMs', icon: Wrench },
+  { to: '/repairs', label: 'Repairs', icon: ArrowRightLeft },
+  { to: '/custody', label: 'My Custody', icon: Hand },
   { to: '/hosts', label: 'Hosts', icon: Server },
   { to: '/admin/users', label: 'Users', icon: UsersIcon, adminOnly: true },
   { to: '/admin/webhooks', label: 'Webhooks', icon: Webhook, adminOnly: true },