fix(awareness): stop the subject echoing itself and cover the echo wiring

Remaining review follow-ups for the sonar pulses.

No self-echo: pulses are born 5 km out (startFraction of the radius),
but contacts nearer than that, the subject included, still lit on every
pulse birth. They now never echo. Just past the birth ring, an echo is
scaled with the front's own fade-in, so a bracket no longer flashes
before a visible front reaches it. The ring flash at the full radius is
unchanged.

Older Safari: the reduced-motion listener falls back to the media
query's addListener / removeListener when addEventListener is missing,
as other modules here already do.

Echo wiring test: a detectionHost test now paints through the real
detection lane with an echo field set, and checks the echo stroke takes
the echo colour on the default style and each style's line colour under
CRT, NVG and FLIR. CURRENT-STATE notes the 5 km no-echo zone.

docs/CURRENT-STATE.md

@@ -4957,7 +4957,7 @@ silently demoting every later lookup for the session.
 - Enabled Data Layer controls report normalized feed health on the button (`LOADING`, `DEGRADED`, `STALE`, `FALLBACK`, or `UNAVAILABLE`) while the metadata line retains the source and reason. A partial CelesTrak group failure keeps the usable catalog and reports `DEGRADED`; a total outage keeps last-good catalog data visible but reports `UNAVAILABLE`.
 - On activation it focuses the nearest currently observed aircraft across the civilian and military feeds, with military winning an exact distance tie; if none are available, it focuses an observed AIS vessel. The aircraft search is deliberately uncapped and one refresh-tick retry handles initially empty feeds. This is an attention-priority navigation shortcut, not a high-risk, affiliation, or threat classification.
 - A selected aircraft, AIS vessel, or mapped installation gets a 250 km **context window** with nearby cohort counts, nearest examples, source labels, and stale/unavailable reasons. It emits `NEARBY` or `UNKNOWN`; no detection, engagement, affiliation, or sensor-activity conclusion is calculated.
-- The window's edge is drawn on the globe as a 250 km range ring: a 4 px polyline with a 2 px Context-blue core inside a 1 px dark halo on each side, 2.5 km above the ellipsoid (`AWARENESS_RANGE_RING_STYLE` in `src/layers/awareness/policy.js`). The halo keeps it legible over bright desert and snow, dark ocean and forest, and under the FLIR, NVG and CRT styles, where the earlier 1 px ellipse outline disappeared. It is a polyline because WebGL draws ellipse outlines at 1 px whatever width is asked for. Three dim sonar pulses (3 px with a 1 px dark outline, same colours, at most 60% opacity) grow slowly from the subject at constant speed, one every 3 s and each taking 9 s, and arrive at the ring at about a third of that. Behind each pulse a radial gradient in the same blue fades inward over 35% of the radius. One unpickable 250 km disc draws both the pulse lines and the gradient, its shader reading the pulse radii and opacities each frame, so a click or tap near a pulse still reaches the contact underneath; the disc is rebuilt only after the subject moves 500 m, and not at all while the pulses rest, and it is hidden while the camera is below its 2.5 km height, where it would sweep across the sky. While pulses run, the ring dims to 40% and flashes to full strength as each pulse reaches it, fading over 1.8 s. As a pulse front crosses a flight, military aircraft or AIS vessel, the detection overlay draws a second bracket around that contact's own bracket, in the pulse blue on the default detection style and in the style's own line colour under NVG, FLIR and CRT, which spreads outward as it fades over 1.4 s (`AWARENESS_RANGE_ECHO`, read through `src/awarenessEcho.js`; no layer's icon is restyled, and mapped installations have no detection bracket). Pulses run for 9 s (three ring flashes) after a selection or a camera move, fading in and out over 1.2 s, then rest: the ring stays on screen at full strength, the pulses, gradient and echoes are hidden, and nothing asks for frames, so a parked Contacts view is quiet again. A moving subject does not wake them, since a flying subject moves on every refresh; a camera that follows a tracked aircraft does keep them running, but that follow already renders every frame. While they run they never hold continuous rendering: each drawn frame arms one render request 80 ms later (the Cyber sonar cadence, `CYBER_SONAR_RENDER_INTERVAL_MS`), so they repaint at about 12.5 fps and never beat the detection lane's 80 ms gate. Under `prefers-reduced-motion`, or in a scene without primitives or preRender and postRender hooks, there are no pulses or echoes and the ring stays on screen; changing the preference mid-session rebuilds the ring. The ring follows a moving subject once it has moved 250 m.
+- The window's edge is drawn on the globe as a 250 km range ring: a 4 px polyline with a 2 px Context-blue core inside a 1 px dark halo on each side, 2.5 km above the ellipsoid (`AWARENESS_RANGE_RING_STYLE` in `src/layers/awareness/policy.js`). The halo keeps it legible over bright desert and snow, dark ocean and forest, and under the FLIR, NVG and CRT styles, where the earlier 1 px ellipse outline disappeared. It is a polyline because WebGL draws ellipse outlines at 1 px whatever width is asked for. Three dim sonar pulses (3 px with a 1 px dark outline, same colours, at most 60% opacity) grow slowly from the subject at constant speed, one every 3 s and each taking 9 s, and arrive at the ring at about a third of that. Behind each pulse a radial gradient in the same blue fades inward over 35% of the radius. One unpickable 250 km disc draws both the pulse lines and the gradient, its shader reading the pulse radii and opacities each frame, so a click or tap near a pulse still reaches the contact underneath; the disc is rebuilt only after the subject moves 500 m, and not at all while the pulses rest, and it is hidden while the camera is below its 2.5 km height, where it would sweep across the sky. While pulses run, the ring dims to 40% and flashes to full strength as each pulse reaches it, fading over 1.8 s. As a pulse front crosses a flight, military aircraft or AIS vessel, the detection overlay draws a second bracket around that contact's own bracket, in the pulse blue on the default detection style and in the style's own line colour under NVG, FLIR and CRT, which spreads outward as it fades over 1.4 s (`AWARENESS_RANGE_ECHO`, read through `src/awarenessEcho.js`; no layer's icon is restyled, and mapped installations have no detection bracket). Pulses are born 5 km out, so the subject itself and anything nearer never echo. Pulses run for 9 s (three ring flashes) after a selection or a camera move, fading in and out over 1.2 s, then rest: the ring stays on screen at full strength, the pulses, gradient and echoes are hidden, and nothing asks for frames, so a parked Contacts view is quiet again. A moving subject does not wake them, since a flying subject moves on every refresh; a camera that follows a tracked aircraft does keep them running, but that follow already renders every frame. While they run they never hold continuous rendering: each drawn frame arms one render request 80 ms later (the Cyber sonar cadence, `CYBER_SONAR_RENDER_INTERVAL_MS`), so they repaint at about 12.5 fps and never beat the detection lane's 80 ms gate. Under `prefers-reduced-motion`, or in a scene without primitives or preRender and postRender hooks, there are no pulses or echoes and the ring stays on screen; changing the preference mid-session rebuilds the ring. The ring follows a moving subject once it has moved 250 m.
 - For a selected live aircraft or vessel, the context window refreshes from the existing tracker/feed position every 750 ms, so nearest distances and cohort counts follow the subject without introducing a duplicate poll loop.
 - Aircraft cohort membership uses every locally loaded, selectable contact inside the 250 km window, including a plane hidden only by horizon culling or because its 3D model owns the visual. Counts and navigation therefore do not change with the current camera angle or billboard/model handoff.
 - Nearby examples in the context panel are focus controls: they use their owning layer's existing selection/tracking path, then frame that contact. Static-installation distances use ellipsoidal surface distance so the count matches the ground-projected context disk.

src/awarenessEcho.js

@@ -13,7 +13,7 @@ import * as Cesium from 'cesium';
  * @property {Cesium.Cartesian3} center Subject's ground point. The publisher
  *   may move it in place; it is read on every query.
  * @property {number} radiusM Range the pulses grow to.
- * @property {{count: number, periodMs: number, startFraction: number}} pulse
+ * @property {{count: number, periodMs: number, startFraction: number, fadeInFraction?: number}} pulse
  * @property {{fadeMs: number, layerIds: string[]}} echo
  * @property {(nowMs: number) => number} [level] How far the pulses are
  *   switched on, 0 to 1; echoes scale with it, so they rest with the pulses.
@@ -50,22 +50,27 @@ export function getAwarenessEchoField() {
  * its distance, fading as (1 - elapsed / `fadeMs`) squared, 0 otherwise. The
  * strongest pulse wins. A front that has wrapped back to the centre still
  * counts for the contact it last crossed, so rim contacts fade out instead of
- * cutting off.
+ * cutting off. Nothing nearer than the birth ring `startFraction` out echoes,
+ * and within the pulse's `fadeInFraction` the echo is scaled down with it.
  * @param {number} nowMs Monotonic clock in milliseconds.
  * @param {number} distanceM Contact's distance from the subject.
  * @param {number} radiusM Range the pulses grow to.
- * @param {{count: number, periodMs: number, startFraction: number}} pulse
+ * @param {{count: number, periodMs: number, startFraction: number, fadeInFraction?: number}} pulse
  * @param {{fadeMs: number}} echo
  * @returns {number} 0 to 1.
  */
 export function awarenessEchoStrength(nowMs, distanceM, radiusM, pulse, echo) {
-  if (!Number.isFinite(distanceM) || distanceM < 0 || distanceM > radiusM)
+  // Pulses are born `startFraction` out, so nothing nearer (the subject
+  // itself, its wingmen) is ever crossed; without this it lit on every birth.
+  if (
+    !Number.isFinite(distanceM) ||
+    distanceM < radiusM * pulse.startFraction ||
+    distanceM > radiusM
+  )
     return 0;
   // The phase at which a pulse front sits at this distance.
-  const touchPhase = Math.max(
-    0,
-    (distanceM / radiusM - pulse.startFraction) / (1 - pulse.startFraction),
-  );
+  const touchPhase =
+    (distanceM / radiusM - pulse.startFraction) / (1 - pulse.startFraction);
   let strength = 0;
   for (let index = 0; index < pulse.count; index++) {
     const cycle = nowMs / pulse.periodMs + index / pulse.count;
@@ -77,7 +82,10 @@ export function awarenessEchoStrength(nowMs, distanceM, radiusM, pulse, echo) {
     if (elapsedMs < echo.fadeMs)
       strength = Math.max(strength, (1 - elapsedMs / echo.fadeMs) ** 2);
   }
-  return strength;
+  // A front still fading in over `fadeInFraction` of its travel echoes no
+  // brighter than it shows.
+  const fadeIn = pulse.fadeInFraction ?? 0;
+  return fadeIn > 0 ? strength * Math.min(1, touchPhase / fadeIn) : strength;
 }
 
 /**

src/awarenessEcho.test.mjs

@@ -45,7 +45,14 @@ test('an echo lights as a pulse front reaches the contact, then fades', () => {
 test('rim contacts fade out after the front wraps; outside the range never', () => {
   const rim = R * 0.999;
   assert.ok(strength(arrival(rim) + echo.fadeMs / 2, rim) > 0.2);
-  assert.ok(strength(pulse.periodMs * 5, 1000) > 0.99, 'inside the start ring');
+  // Inside the ring pulses are born on, nothing is ever crossed: the
+  // subject and anything within 5 km never echo, at any moment.
+  const inner = R * pulse.startFraction;
+  for (let ms = 0; ms < pulse.periodMs; ms += 10) {
+    assert.equal(strength(ms, 0), 0, 'the subject itself');
+    assert.equal(strength(ms, inner - 1), 0);
+  }
+  assert.ok(strength(pulse.periodMs * 5, inner) > 0.99, 'the birth ring');
   for (let ms = 0; ms < pulse.periodMs; ms += 50)
     assert.equal(strength(ms, R + 1), 0);
   assert.equal(strength(0, Number.NaN), 0);
@@ -74,9 +81,12 @@ test('awarenessEchoAt reads the published field, by layer, at ground level', (t)
         awarenessEchoAt('flights', contact, t0 + 300),
     ) < 0.01,
   );
-  // The field's centre is read in place, so a moved subject moves the echo.
-  Cesium.Cartesian3.clone(contact, center);
-  assert.ok(awarenessEchoAt('flights', contact, pulse.periodMs * 7) > 0.99);
+  // The field's centre is read in place, so a moved subject moves the echo:
+  // about 50 km farther, the contact lights at its new distance's moment.
+  Cesium.Cartesian3.clone(Cesium.Cartesian3.fromDegrees(3.5, 26.1, 0), center);
+  const moved = Cesium.Cartesian3.distance(center, contact);
+  assert.ok(Math.abs(moved - d) > 1000);
+  assert.ok(awarenessEchoAt('flights', contact, arrival(moved)) > 0.99);
   assert.equal(awarenessEchoAt('flights', null, t0), 0);
   clearAwarenessEchoField();
   assert.equal(getAwarenessEchoField(), null);
@@ -107,3 +117,19 @@ test('echoes scale with the field level and rest with the pulses', (t) => {
   level = 0;
   assert.equal(awarenessEchoAt('flights', contact, t0), 0);
 });
+
+test('near the subject an echo is no brighter than the fading-in front', () => {
+  const fading = { ...pulse, fadeInFraction: 0.08 };
+  const at = (distanceM) =>
+    awarenessEchoStrength(arrival(distanceM), distanceM, R, fading, echo);
+  // Born at 5 km, the front reaches full strength 8% of the way out.
+  const full = R * (fading.startFraction + 0.08 * (1 - fading.startFraction));
+  assert.equal(at(R * fading.startFraction), 0);
+  const halfway = (R * fading.startFraction + full) / 2;
+  assert.ok(Math.abs(at(halfway) - 0.5) < 0.01, `${at(halfway)}`);
+  assert.ok(at(full + 1) > 0.99);
+  assert.ok(
+    at(R * 0.999) > 0.99,
+    'the rim, and so the ring flash, is unchanged',
+  );
+});

src/data/detectionHost.test.mjs

@@ -24,6 +24,10 @@ import {
   setOverlayEntries,
 } from '../overlays/worldOverlay.js';
 import { DETECTION_THEME_MAP } from '../overlays/worldOverlayTokens.js';
+import {
+  clearAwarenessEchoField,
+  setAwarenessEchoField,
+} from '../awarenessEcho.js';
 import { composeLabel, resolveTier } from './detectionDraw.js';
 
 test('detection diagnostics count rendered fading rows instead of absent selected identities', () => {
@@ -627,6 +631,54 @@ test('surveillance military tier reaches the dedicated render target as shipped
   }
 });
 
+test('Global Context echo brackets reach the canvas in the detection style colour', () => {
+  const env = installEnvironment();
+  // Fronts every millisecond with a long fade, so the contact is lit on
+  // whatever frame paints; a distinctive width picks the echo stroke out.
+  const echo = {
+    layerIds: ['military'],
+    fadeMs: 60_000,
+    color: 'rgb(1, 2, 3)',
+    spreadPx: 8,
+    lineWidth: 3.25,
+  };
+  const echoStrokes = () =>
+    env.detectionCtx.calls
+      .filter(([name, , , width]) => name === 'stroke' && width === echo.lineWidth)
+      .map(([, , style]) => style);
+  try {
+    setAwarenessEchoField({
+      center: Cesium.Cartesian3.fromDegrees(0, 89, 0),
+      radiusM: 250_000,
+      pulse: { count: 1000, periodMs: 1000, startFraction: 0 },
+      echo,
+    });
+    initWorldOverlay(env.viewer);
+    initDetection(env.viewer, [militaryLayer()], () => {});
+    setMode('DENSE');
+    setDetectionStyle('normal');
+    settleFrame(env);
+    assert.ok(echoStrokes().length > 0, 'the echo bracket is painted');
+    assert.ok(echoStrokes().every((style) => style === echo.color));
+
+    // CRT, NVG and FLIR keep their own palettes.
+    for (const style of ['retro', 'surveillance', 'thermal']) {
+      env.detectionCtx.calls.length = 0;
+      setDetectionStyle(style);
+      settleFrame(env);
+      const strokes = echoStrokes();
+      assert.ok(strokes.length > 0, style);
+      assert.ok(
+        strokes.every((stroke) => stroke === DETECTION_THEME_MAP[style].line),
+        `${style} echoes take the style line colour, got ${strokes}`,
+      );
+    }
+  } finally {
+    clearAwarenessEchoField();
+    env.cleanup();
+  }
+});
+
 test('pathological detection paint holds alternate frames without freezing shared lanes', () => {
   // Opts into the telemetry banner: the held-frame assertions count banner paints.
   const env = installEnvironment({ search: '?detectDebug=1' });

src/layers/awareness/rangeRing.test.mjs

@@ -49,20 +49,30 @@ function luminance(color) {
  * test; `motion.set(on)` flips it later and tells its listeners, as the
  * browser does.
  */
-function ringRendering(t, { reducedMotion = false } = {}) {
+function ringRendering(t, { reducedMotion = false, legacyQuery = false } = {}) {
   const previous = globalThis.matchMedia;
   const listeners = new Set();
-  const query = {
-    get matches() {
-      return reducedMotion;
-    },
-    addEventListener(type, listener) {
-      if (type === 'change') listeners.add(listener);
-    },
-    removeEventListener(type, listener) {
-      if (type === 'change') listeners.delete(listener);
-    },
-  };
+  // `legacyQuery` is a MediaQueryList as Safari before 14 shipped it, with
+  // only addListener / removeListener.
+  const query = legacyQuery
+    ? {
+        get matches() {
+          return reducedMotion;
+        },
+        addListener: (listener) => listeners.add(listener),
+        removeListener: (listener) => listeners.delete(listener),
+      }
+    : {
+        get matches() {
+          return reducedMotion;
+        },
+        addEventListener(type, listener) {
+          if (type === 'change') listeners.add(listener);
+        },
+        removeEventListener(type, listener) {
+          if (type === 'change') listeners.delete(listener);
+        },
+      };
   globalThis.matchMedia = (media) =>
     media === '(prefers-reduced-motion: reduce)'
       ? query
@@ -693,6 +703,21 @@ test('turning reduced motion on mid-session stops the pulses, and off restarts t
   assert.equal(motion.listeners(), 0);
 });
 
+test('a reduced-motion change reaches older Safari through addListener', (t) => {
+  const { entities, scene, rendering, motion, state } = ringRendering(t, {
+    legacyQuery: true,
+  });
+  state.subject = flight(3);
+  rendering.renderVisual(state.subject);
+  assert.equal(scene.primitives.length, 1);
+  assert.equal(motion.listeners(), 1);
+  motion.set(true);
+  assert.equal(scene.primitives.length, 0);
+  assert.equal(entities.values[0].polyline.material.color.isConstant, true);
+  rendering.clearVisual();
+  assert.equal(motion.listeners(), 0);
+});
+
 test('a refresh after reduced motion changed rebuilds the visual too', (t) => {
   const { entities, rendering, motion } = ringRendering(t);
   rendering.renderVisual(flight(3));

src/layers/awareness/rendering.js

@@ -758,7 +758,10 @@ export function createRendering({
     const onMotionChange = () => {
       if (layerState.subject) renderVisual(layerState.subject);
     };
-    motionQuery?.addEventListener?.('change', onMotionChange);
+    // Safari before 14 has only the older addListener / removeListener.
+    if (motionQuery?.addEventListener)
+      motionQuery.addEventListener('change', onMotionChange);
+    else motionQuery?.addListener?.(onMotionChange);
 
     layerState.visual = {
       key,
@@ -770,8 +773,11 @@ export function createRendering({
       reducedMotion,
       wake,
       stopPulses,
-      removeMotionListener: () =>
-        motionQuery?.removeEventListener?.('change', onMotionChange),
+      removeMotionListener: () => {
+        if (motionQuery?.removeEventListener)
+          motionQuery.removeEventListener('change', onMotionChange);
+        else motionQuery?.removeListener?.(onMotionChange);
+      },
     };
     governorRequestRender('awareness-visual');
   }