Merge remote-tracking branch 'upstream/main' into core-rb2

# Conflicts:
#	CHANGELOG.md
#	build/vite.js
#	scripts/package-boundaries.json
#	server/standalone/vite.config.js
#	src/app/scene.js
#	src/layers/vessels/queries.js
#	src/standalone/application.js
#	src/tooling/viteBuild.test.mjs
#	src/ui/cockpitInstruments.js
#	src/ui/layerPanel.js
#	src/ui/panelPositionControls.js

src/layers/satellites/orbits.js

@@ -8,6 +8,7 @@ import {
   twoline2satrec,
 } from 'satellite.js';
 import { findNextSatellitePass } from '../../data/satellitePass.js';
+import { parseTleText } from '../../sources/tle.js';
 import { ORBIT_PATH_STEPS, ISS_NORAD } from './policy.js';
 
 export function createOrbits({ state: layerState, services, parts, source }) {
@@ -40,24 +41,7 @@ export function createOrbits({ state: layerState, services, parts, source }) {
   /**
    * Parse TLE text into array of { name, line1, line2 } objects.
    */
-
-  function parseTLE(text) {
-    const lines = text
-      .trim()
-      .split('\n')
-      .map((l) => l.trim())
-      .filter((l) => l.length > 0);
-    const result = [];
-    for (let i = 0; i < lines.length - 2; i += 3) {
-      const name = lines[i];
-      const line1 = lines[i + 1];
-      const line2 = lines[i + 2];
-      if (line1.startsWith('1 ') && line2.startsWith('2 ')) {
-        result.push({ name, line1, line2 });
-      }
-    }
-    return result;
-  }
+  const parseTLE = parseTleText;
 
   /**
    * Propagate satellite position at a given JS Date.

src/layers/satellites/source.js

@@ -19,7 +19,10 @@ export function createSatelliteSource({
       const response = await fetchImpl(`/api/celestrak/${group}`, { signal });
       const text = response.ok ? await response.text() : '';
       signal?.throwIfAborted();
-      return { ok: response.ok, status: response.status, text };
+      // The proxy serves its last copy, marked STALE-ERROR, when CelesTrak
+      // is down.
+      const stale = response.headers?.get?.('x-tle-cache') === 'STALE-ERROR';
+      return { ok: response.ok, status: response.status, text, stale };
     },
   };
 }