Add ADS-B, AIS, and ALPR map layers with live CoT streaming (#36)

## Summary

- **ADS-B & AIS:** OpenSky and AISStream OSINT feeds upsert into the CoT store; tactical tracks still arrive via adsbcot/aiscot on `:8089`. Map clients subscribe via `GET /api/cot/stream` (SSE) with viewport bbox filtering and Air / Surface / Team layer toggles.
- **ALPR (Flock/OSM):** Toggleable license-plate reader layer sourced from OpenStreetMap, with SQLite cache, Overpass fallback, tiled viewport fetching, and clustered markers with direction cones.
- **Map performance:** Ring-based tile selection (fixes zoom-out crash), immutable tile cache, incremental marker sync, split cluster load/query, and padded SSE bbox to reduce reconnect churn.

## Docs

- `docs/tracking.md` — ADS-B/AIS accuracy tiers, freshness, self-hosted receivers, optional OSINT API keys
- `docs/map-and-cameras.md` — ALPR layer and map behavior updates

---------

Co-authored-by: Madison Grubb <madison@elastiflow.com>
Reviewed-on: #36

test/nuxt/useCameras.spec.js

@@ -15,26 +15,12 @@ describe('useCameras', () => {
     setupEndpoints(() => ({
       devices: [{ id: '1', name: 'Test', lat: 37.7, lng: -122.4, streamUrl: '', sourceType: 'mjpeg', device_type: 'feed' }],
       liveSessions: [],
-      cotEntities: [],
     }))
     const wrapper = await mountSuspended(Index)
     await wait()
     expect(wrapper.findComponent({ name: 'KestrelMap' }).exists()).toBe(true)
   })
 
-  it('exposes cotEntities from API', async () => {
-    const cotEntities = [{ id: 'cot-1', lat: 38, lng: -123, label: 'ATAK1' }]
-    setupEndpoints(() => ({
-      devices: [],
-      liveSessions: [],
-      cotEntities,
-    }))
-    const wrapper = await mountSuspended(Index)
-    await wait()
-    const map = wrapper.findComponent({ name: 'KestrelMap' })
-    expect(map.props('cotEntities')).toEqual(cotEntities)
-  })
-
   it('handles API error and falls back to empty devices and liveSessions', async () => {
     setupEndpoints(() => {
       throw new Error('network')