feat(live-atc): forward aircraft position, un-throttle bridge polling

- NormalizedTelemetry carries lat/lon (0/0 no-GPS guard, position in the
  change-detection signature) so the backend can derive distance triggers
- bridge polling moves from setInterval to a Worker tick: with the sim in the
  foreground the /live-atc tab is backgrounded and Chrome throttles plain
  intervals to ~1/min — telemetry-driven ATC lagged behind the silence fallback

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shared/utils/bridgeTelemetry.ts

@@ -7,16 +7,22 @@ export function normalizeSimFreq(value: unknown): string | null {
 }
 
 // Map the raw bridge telemetry (SimConnect-style field names) to the
-// sim-agnostic contract the backend understands. distance_to_*_nm are omitted
-// until pm.vue has a reliable airport-coordinate source to compute them from;
-// heading is currently true (bridge only reports true) — magnetic correction is
-// needed before any localizer/heading trigger can rely on it.
+// sim-agnostic contract the backend understands. The raw lat/lon position is
+// forwarded so the backend can derive distance_to_dep_nm / distance_to_dest_nm
+// (it has the airport coordinates via the session's ICAO codes); heading is
+// currently true (bridge only reports true) — magnetic correction is needed
+// before any localizer/heading trigger can rely on it.
 export function normalizeBridgeTelemetry(raw: any): NormalizedTelemetry | null {
   if (!raw || typeof raw !== 'object') return null
   const num = (v: unknown): number | undefined => {
     const n = typeof v === 'number' ? v : Number(v)
     return Number.isFinite(n) ? n : undefined
   }
+  const lat = num(raw.PLANE_LATITUDE)
+  const lon = num(raw.PLANE_LONGITUDE)
+  // 0/0 is the bridge's "no GPS data" default — don't forward it as a position.
+  const hasPosition =
+    lat !== undefined && lon !== undefined && (Math.abs(lat) > 0.1 || Math.abs(lon) > 0.1)
   return {
     altitude_ft: num(raw.PLANE_ALTITUDE),
     ias_kts: num(raw.AIRSPEED_INDICATED),
@@ -24,15 +30,19 @@ export function normalizeBridgeTelemetry(raw: any): NormalizedTelemetry | null {
     vs_fpm: num(raw.VERTICAL_SPEED),
     heading_deg: num(raw.PLANE_HEADING_DEGREES_TRUE),
     on_ground: typeof raw.SIM_ON_GROUND === 'boolean' ? raw.SIM_ON_GROUND : undefined,
+    ...(hasPosition ? { lat, lon } : {}),
   }
 }
 
 // Only forward telemetry that meaningfully changed, so idle cruise doesn't POST
 // an identical tick every poll. Rounded so tiny jitter doesn't count as change.
+// Position rounds at ~0.01° (≈0.6 nm) so a moving aircraft keeps ticking the
+// backend's distance triggers without spamming while parked.
 export function telemetrySignature(t: NormalizedTelemetry): string {
   const r = (v: number | undefined, step: number) => (v === undefined ? '_' : Math.round(v / step))
   return [
     r(t.altitude_ft, 100), r(t.ias_kts, 5), r(t.gs_kts, 5),
     r(t.vs_fpm, 100), r(t.heading_deg, 5), t.on_ground ? 'G' : 'A',
+    r(t.lat, 0.01), r(t.lon, 0.01),
   ].join('|')
 }