fix(flights): read a 359.6° track as 0° in the voice context, not 360°

The voice context records for a selected flight or military contact
rounded the track without wrapping, so a contact on 359.5° or more was
described to the assistant as heading "360°". Both now wrap after
rounding: 359.6° reads "0°", 359.4° still reads "359°".

src/layers/flights/ownership.test.mjs

@@ -3,6 +3,7 @@ import assert from 'node:assert/strict';
 import { createCivilFlightLayer } from './index.js';
 import { createFlightState } from './state.js';
 import { createEnrichment } from './enrichment.js';
+import { createTracking } from './tracking.js';
 
 function services() {
   const names = [
@@ -124,3 +125,24 @@ test('a synchronous enrichment failure stays bounded and releases its slot', asy
   await new Promise((done) => setImmediate(done));
   assert.equal(flightState._enrichActive, 0);
 });
+
+test('voice context reads a track that rounds to north as 0°, not 360°', () => {
+  const tracking = createTracking({
+    flightState: {
+      feed: { _lastSource: 'Fixture aircraft' },
+      records: { data: new Map() },
+    },
+    services: services(),
+    parts: {
+      queries: {
+        _describeFlight: () => ({ track: 359.6, altitudeM: 9000 }),
+        _contactLabel: () => 'AAL1',
+      },
+    },
+    layer: {},
+  });
+  assert.equal(
+    tracking._contextSubjectMetadata('abc123').properties.heading,
+    '0°',
+  );
+});

src/layers/flights/tracking.js

@@ -125,8 +125,9 @@ export function createTracking({
         speed: Number.isFinite(described.velocityMps)
           ? `${Math.round(described.velocityMps * 1.944)} kt`
           : '',
+        // 359.5° and above rounds to north; modulo keeps it from reading 360°.
         heading: Number.isFinite(described.track)
-          ? `${Math.round(described.track)}°`
+          ? `${Math.round(described.track) % 360}°`
           : '',
         route: route || '',
         icao24,

src/layers/military/ownership.test.mjs

@@ -2,6 +2,7 @@ import test from 'node:test';
 import assert from 'node:assert/strict';
 import { createMilitaryFlightLayer } from './index.js';
 import { createFlightState } from './state.js';
+import { createTracking } from './tracking.js';
 
 function services() {
   const names = [
@@ -211,3 +212,27 @@ test('a newly seen military contact appears at its delayed position, not ahead o
     `expected about ${Math.round(expectedM)} m behind the fix, got ${Math.round(behindM)} m`,
   );
 });
+
+test('voice context reads a track that rounds to north as 0°, not 360°', () => {
+  const stubs = services();
+  stubs.aircraftPresentation = { tr3bTypeLabel: (id, type) => type };
+  const tracking = createTracking({
+    flightState: {
+      feed: { _lastSource: 'Fixture aircraft' },
+      records: { data: new Map() },
+    },
+    services: stubs,
+    parts: {
+      queries: {
+        _describeFlight: () => ({ track: 359.6, callsign: 'RCH123' }),
+        _toCleanText: (value) => value || '',
+        _formatAltitude: () => '',
+      },
+    },
+    layer: {},
+  });
+  assert.equal(
+    tracking._contextSubjectMetadata('ae1234').properties.heading,
+    '0°',
+  );
+});

src/layers/military/tracking.js

@@ -119,8 +119,9 @@ export function createTracking({
         speed: Number.isFinite(described.velocityMps)
           ? `${Math.round(described.velocityMps * 1.944)} kt`
           : '',
+        // 359.5° and above rounds to north; modulo keeps it from reading 360°.
         heading: Number.isFinite(described.track)
-          ? `${Math.round(described.track)}°`
+          ? `${Math.round(described.track) % 360}°`
           : '',
         icao24,
         // Honesty cue: the contact is coasting on dead reckoning, so the