Retire the legacy Machine model (ADR-001 cutover)

The asset/computer model is now the single source of truth. Remove the Machine
instance layer end to end:

- Delete models Machine, MachineStatus, PCType, MachineRelationship,
  InstalledApp, PrinterData; keep MachineType (models.machinetypeid still
  references it).
- Delete the /api/machines, /api/statuses, /api/pctypes blueprints and the
  legacy /api/printers/legacy (PrinterData) blueprint.
- Drop the deprecated communications.machineid column and its FK.
- Migration 7c01 drops tables machines, machinestatuses, pctypes,
  machinerelationships, installedapps, printerdata (idempotent).
- Fix remaining readers (applications install counts) to ComputerInstalledApp.
- Frontend: remove dead machinesApi/statusesApi/pctypesApi wrappers; repoint
  the PC Types settings page at computer types.

143 tests pass; all asset/computer/dashboard/report/collector endpoints 200.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

shopdb/cli/__init__.py

@@ -42,7 +42,7 @@ def seed_cli():
 def seed_reference_data():
     """Seed reference data (machine types, statuses, etc.)."""
     from shopdb.extensions import db
-    from shopdb.core.models import MachineType, MachineStatus, OperatingSystem, AssetStatus
+    from shopdb.core.models import MachineType, OperatingSystem, AssetStatus
     from shopdb.core.models.relationship import RelationshipType
 
     # Machine types
@@ -67,21 +67,6 @@ def seed_reference_data():
             mt = MachineType(**mt_data)
             db.session.add(mt)
 
-    # Machine statuses
-    statuses = [
-        {'status': 'In Use', 'description': 'Currently in use', 'color': '#28a745'},
-        {'status': 'Spare', 'description': 'Available as spare', 'color': '#17a2b8'},
-        {'status': 'Retired', 'description': 'No longer in use', 'color': '#6c757d'},
-        {'status': 'In Repair', 'description': 'Currently being repaired', 'color': '#ffc107'},
-        {'status': 'Pending', 'description': 'Pending installation', 'color': '#007bff'},
-    ]
-
-    for s_data in statuses:
-        existing = MachineStatus.query.filter_by(status=s_data['status']).first()
-        if not existing:
-            s = MachineStatus(**s_data)
-            db.session.add(s)
-
     # Asset statuses (canonical set - the asset model is the contract)
     asset_statuses = [
         {'status': 'In Use', 'description': 'Currently in use', 'color': '#28a745'},