Move the changelog entry to changelog.d and clear review leftovers

The entry now lives in changelog.d/1471-context-panel-cleanup.md with
credit, as CONTRIBUTING asks, and CHANGELOG.md is back to main.

CURRENT-STATE no longer lists a compact Radio power control and scopes
the readability description to what Cyber keeps. The responsive glow
comment no longer cites the removed Radio popover, and qa-radio's
pick-buffer comment is back above settleRadioFrames.

Four test fixtures stop stubbing the removed launcher sync, and
PanelChrome drops the _syncRailPanelCollapseButton pass-through, wiring
the layout controller straight to _syncPanelCollapseButton.

src/ui/panelChrome.js

@@ -71,8 +71,7 @@ export class PanelChrome {
         variant: this.hud.getVariant(),
       }),
       scheduleCockpitLayout: () => this.cockpitView?.scheduleContextLayout(),
-      syncPanelCollapseButton: (panel) =>
-        this._syncRailPanelCollapseButton(panel),
+      syncPanelCollapseButton: (panel) => this._syncPanelCollapseButton(panel),
       readDisplayScrollTop: () =>
         this._displayPortalScrollRestoreOwner === 'standard'
           ? this._standardDisplayScrollTop
@@ -292,10 +291,6 @@ export class PanelChrome {
     return this._panelLayout._scheduleLeftPanelLayout(options0);
   }
 
-  _syncRailPanelCollapseButton(panelEl) {
-    this._syncPanelCollapseButton(panelEl);
-  }
-
   _syncPanelCollapseButton(panelEl) {
     const isRightRail = [
       'pp-toggles',

src/ui/radioPresentation.playbackError.test.mjs

@@ -22,7 +22,6 @@ function render(audioError) {
     destroyed: false,
     _radioPanel: el(),
     _radioPlaybackState: el(),
-    _syncContextRadioLauncherState() {},
     actions: {
       getLifecycle: () => null,
       preservePanelStateDuringClear: () => false,

src/ui/radioPresentationTransition.test.mjs

@@ -27,7 +27,6 @@ for (const lifecycleState of ['enabling', 'disabling']) {
         destroyed: false,
         _radioPanel: el(),
         _radioEnableBtn: enable,
-        _syncContextRadioLauncherState() {},
         actions: {
           getLifecycle: () => ({
             lifecycleState,

src/ui/shellLifecycle.test.mjs

@@ -281,7 +281,7 @@ test('weather rail orders between CCTV and Context, observes and syncs chrome',
     const weather = f.nodes.get('weather-panel');
     stack.children = [weather, f.nodes.get('global-context-panel')];
     const synced = [];
-    const chrome = { _syncContextRadioLauncherState() {} };
+    const chrome = {};
     const owner = new PanelLayoutController({
       readHud: () => ({}),
       scheduleCockpitLayout() {},

src/ui/styles/responsive.css

@@ -205,7 +205,7 @@
      under the expanded panel plus a vertical scrollbar that scrolls nothing
      but glow. Pin the glow to the panel box here — its blur is ink overflow,
      which never scrolls — instead of clipping the rail, which would also clip
-     legitimate content such as the Context radio popover. */
+     legitimate content that extends past a panel's edge. */
   #left-panel-stack .panel-glow,
   #right-context-rail .panel-glow {
     inset: 0;