chore: remove the remaining unused local bindings

An ESLint no-unused-vars scan over src, server, scripts, tools, build
and pinokio, repeated until it is stable, reported these.

Runtime modules keep every call and drop only the unread binding:
- src/ui/cockpitInput.js: the unread result of enter()/exit().
- src/layers/launches/rendering.js: the unread entity returned by
  entities.add().
- src/layers/radio/rendering.js: the unread map key in the horizon scan,
  which now iterates the map's values.

QA scripts and tools drop an unused helper, two unused in-page module
imports, unused counters and destructured fields, and an unread wait
result. Tests drop source files read into variables that no assertion
uses, redundant StyleManager imports (the shell-source helper already
imports it), and unused destructured fields.

The one remaining report is the `_` loop variable in src/tools/schema.js,
which counts iterations and is intentional.

src/mapSourceFocus.test.mjs

@@ -1,6 +1,5 @@
-import { readShellSource, shellMethod } from './testSupport/readShellSource.mjs';
+import { shellMethod } from './testSupport/readShellSource.mjs';
 import { expandApplicationHtml } from '../build/application-html.js';
-import { StyleManager } from './ui/applicationShell.js';
 import { createHoverDisclosure, collapsePanelOnEscape } from './ui/panelDisclosure.js';
 import test from 'node:test';
 import assert from 'node:assert/strict';
@@ -8,7 +7,6 @@ import { readFileSync } from 'node:fs';
 import { msg, t } from './i18n/index.js';
 
 // Exercise the installed event routes and central close method, without WebGL.
-const source = readShellSource();
 const markup = expandApplicationHtml(readFileSync(new URL('../index.html', import.meta.url), 'utf8'));
 const locationMarkup = markup.slice(markup.indexOf('<div id="location-bar"'), markup.indexOf('<div id="left-panel-stack"'));
 const locationToggleMarkup = locationMarkup.match(/<button\b([^>]*\bid="location-bar-toggle"[^>]*)>([\s\S]*?)<\/button>/);