feat: RouterBOOT upgrade support, update UI overhaul, discovery fixes (v0.10.6 Beta)

RouterOS vs RouterBOOT distinction:
- Rename "Firmware Updates" → "RouterOS Updates" everywhere (Config tab,
  dashboard banner, devices list tooltip) to accurately reflect what is
  being updated
- Add RouterBOOT bootloader upgrade support as a distinct operation:
  new DeviceCollector methods checkRouterboardUpgrade() and
  installRouterboardUpgrade() using /system/routerboard/print and
  /system/routerboard/upgrade
- New API endpoints: POST /api/devices/:id/check-routerboard and
  POST /api/devices/:id/install-routerboard
- Daily poller now also checks RouterBOOT upgrade status while already
  connected during firmware check cycle, with first-discovery alerts

Config tab update panel:
- Combine RouterOS and RouterBOOT into a single "Software & Firmware
  Updates" card with two subsections separated by a divider
- Pre-populate both sections from stored DB state on load — no longer
  requires a manual "Check" click to see a known pending update
- Enforce update order: when both are pending, show a blue info banner
  explaining RouterOS must be installed first, and disable the
  RouterBOOT "Upgrade & Reboot" button until the RouterOS update clears
- Fix GET /api/devices/:id to include firmware_update_available,
  latest_ros_version, routerboard_upgrade_available, upgrade_firmware_version
  (these were missing from the detail endpoint)

Dashboard & devices list:
- Combined amber banner now shows two distinct rows: RouterOS (N) with
  device links and RouterBOOT (N) with device links — one dismiss for both
- Devices list: amber ArrowUpCircle = RouterOS update, blue Cpu icon =
  RouterBOOT upgrade, each with distinct tooltips
- Fix GET /api/devices (list) to include routerboard_upgrade_available and
  upgrade_firmware_version (these were missing, causing RouterBOOT
  notifications to never appear on the dashboard)

DB migration:
- Add routerboard_upgrade_available BOOLEAN DEFAULT FALSE
- Add upgrade_firmware_version VARCHAR(20)

Discovery system fixes:
- Fix duplicate entries: replace single-key (mac || ip || identity) dedup
  with three cross-referenced indexes so a neighbor seen via LLDP by one
  device and via MNDP by another always merges into one row
- Fix offline devices persisting: handleDeviceFailure now deletes
  topology_links for the offline device (same pattern as clients)
- Add periodic stale-link sweep every 15 min that removes topology_links
  rows older than 20 min as a safety net for devices that go offline
  without cleanly triggering handleDeviceFailure

frontend/src/services/api.ts

@@ -179,6 +179,9 @@ export const devicesApi = {
     api.delete(`/devices/${id}/ip-addresses/${encodeURIComponent(addrId)}`),
   checkUpdate: (id: number) =>
     api.post<Record<string, string>>(`/devices/${id}/check-update`),
+  checkRouterboard: (id: number) =>
+    api.post<{ currentFirmware: string; upgradeFirmware: string; upgradeAvailable: boolean }>(`/devices/${id}/check-routerboard`),
+  installRouterboard: (id: number) => api.post(`/devices/${id}/install-routerboard`),
   getHardware: (id: number) =>
     api.get<{ health: Record<string, string>[]; disks: Record<string, string>[] }>(`/devices/${id}/hardware`),
   installUpdate: (id: number) => api.post(`/devices/${id}/install-update`),