Carry server structural rejections into Radio diagnostics

The proxy now skips malformed upstream rows individually but counts
them, capped at 10,000, in the catalog metadata and the /stations
envelope (rejectedStationCount). The count never fails health policy,
so an otherwise healthy generation is still accepted. The client
validates the field, adds its own rejected rows after admission, and
reports degraded coverage when either side skipped rows. Adds an
end-to-end proxy-to-client test and aligns DATA_SOURCES.md and
CURRENT-STATE.md.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/data/radio.test.mjs

@@ -723,13 +723,47 @@ test('unusable directory responses preserve warm client state atomically', async
     assert.equal(getRadioUIState().stale, false);
     assert.equal(getRadioAcceptedCatalogSnapshot().generation, 2);
     assert.equal(getRadioAcceptedCatalogSnapshot().stations[0].id, replacement.id);
+    // Server-side structural rejections are combined with client rejections
+    // after admission; the healthy generation is still accepted.
     globalThis.fetch = async () => new Response(JSON.stringify({
-      stations: [{ id: 'malformed' }], stale: false, degraded: false,
+      stations: [replacement, { id: 'malformed' }], stale: false, degraded: false,
       acceptedGeneration: 3, catalogInstance: 'qa-instance-a', updatedAt: now,
+      rejectedStationCount: 2,
     }));
     await radioLayer.update();
-    assert.equal(getRadioAcceptedCatalogSnapshot().generation, 2);
+    assert.equal(getRadioUIState().rejectedStationCount, 3);
+    assert.equal(getRadioUIState().degraded, true);
+    assert.equal(getRadioAcceptedCatalogSnapshot().generation, 3);
+    globalThis.fetch = async () => new Response(JSON.stringify({
+      stations: [replacement], stale: false, degraded: false,
+      acceptedGeneration: 4, catalogInstance: 'qa-instance-a', updatedAt: now,
+      rejectedStationCount: 10_000,
+    }));
+    await radioLayer.update();
+    assert.equal(getRadioUIState().rejectedStationCount, 10_000);
+    assert.equal(getRadioAcceptedCatalogSnapshot().generation, 4);
+    for (const rejectedStationCount of [-1, 1.5, '2', null, 10_001]) {
+      globalThis.fetch = async () => new Response(JSON.stringify({
+        stations: [replacement], stale: false, degraded: false,
+        acceptedGeneration: 5, catalogInstance: 'qa-instance-a', updatedAt: now,
+        rejectedStationCount,
+      }));
+      await radioLayer.update();
+      assert.equal(getRadioAcceptedCatalogSnapshot().generation, 4);
+      assert.equal(getRadioUIState().stale, true);
+    }
+    globalThis.fetch = async () => new Response(JSON.stringify({
+      stations: [{ id: 'malformed' }], stale: false, degraded: false,
+      acceptedGeneration: 5, catalogInstance: 'qa-instance-a', updatedAt: now,
+    }));
+    await radioLayer.update();
+    assert.equal(getRadioAcceptedCatalogSnapshot().generation, 4);
     assert.equal(getRadioUIState().stale, true);
+    assert.equal(getRadioUIState().rejectedStationCount, 10_000);
+    radioLayer.destroy();
+    radioLayer.init(viewer);
+    assert.equal(getRadioUIState().rejectedStationCount, 0);
+    assert.equal(getRadioUIState().degraded, false);
   } finally {
     globalThis.fetch = originalFetch;
     radioLayer.destroy();