feat(13-02): add wireless_links table migration, ORM model, register both models

- Migration 033 creates wireless_links with state machine, missed_polls, RLS
- WirelessLink model with LinkState enum (discovered/active/degraded/down/stale)
- Register DeviceInterface, WirelessLink, LinkState in models __init__

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/models/__init__.py

@@ -18,6 +18,8 @@ from app.models.audit_log import AuditLog
 from app.models.maintenance_window import MaintenanceWindow
 from app.models.api_key import ApiKey
 from app.models.config_backup import RouterConfigSnapshot, RouterConfigDiff, RouterConfigChange
+from app.models.device_interface import DeviceInterface
+from app.models.wireless_link import WirelessLink, LinkState
 
 __all__ = [
     "Tenant",
@@ -45,4 +47,7 @@ __all__ = [
     "RouterConfigSnapshot",
     "RouterConfigDiff",
     "RouterConfigChange",
+    "DeviceInterface",
+    "WirelessLink",
+    "LinkState",
 ]