fix(orchestrator): release a station's redirect targets in media-src

Deutschlandfunk stayed silent: its signed URL answers 302 to
f111.rndfnk.com, an origin the signed media-src never listed, so the
browser blocked the redirected load and reported only the station's own
URL in securitypolicyviolation.

The hub now resolves each https stream's redirect chain server side when
a settings save adds or changes it and stores the extra origins as the
stream's via list. media-src lists them next to the signed origins. A CDN
host of three or more labels widens to its siblings (*.rndfnk.com); an
IP, a two-label host and a name under a country code's generic second
level stay exact.

Hardening:

- Only the signed URL itself may lie at a non-global address; every
  redirect hop dials a global address only, checked on the address
  actually dialed (NAT64 and IPv4-compatible IPv6 count by the embedded
  IPv4 address).
- A resolve answers within three socket timeouts even for a server that
  drips its headers; a late probe goes on in a daemon thread and a url
  still in flight is not probed twice.
- A failed resolution stores via null and retries on a save ten minutes
  later; the radio page says so instead of blaming the CSP.
- A save whose settings changed while it was resolved fails instead of
  overwriting them (compare and set under the settings lock).
- A new stream URL at an already signed origin takes the passkey too.
- Settings written before via existed load as via [] and never dial.

Residuals:

- The passkey proof is spent before the resolve, so a save racing
  another one fails and the operator signs again.
- A save that hits a due retry blocks up to twelve seconds and may
  reload the page.
- A page loaded before the upgrade throws on the missing via until it
  reloads.
- A private multi-tenant suffix such as github.io still widens.
- getaddrinfo has no timeout; it runs inside the daemon thread.

Operator step after install: remove Deutschlandfunk in Radio, Sender
bearbeiten, save, add it again and save with the passkey.

🎯 Fix: 92 %
💥 Break: 4 %
💸 Cost: 100 %
⏱️ Time: –
🛡️ Security: 100 %
🏆 Score: 88
🚦 Gate: ✅ 90/5, cost and time <= 100, security 100 %

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_hub_radio_trouble.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import json
+import subprocess
+import unittest
+
+from hub_support import AMBIENCE
+from kvb_orchestrator.settings import stream_origin
+
+DLF = "https://st01.sslstream.dlf.de/dlf/01/high/aac/stream.aac?aggregator=web"
+OTHER = "https://radio.example/morgen"
+URLS = [DLF, "https://Radio.Example:443/zweiter?x=1", "http://10.0.0.5:8000/nacht", "https://other.example:8443/", "http://radio.example:80/x"]
+PROBE = """
+const A = require(process.argv[1]);
+const [DLF, OTHER] = JSON.parse(process.argv[2]);
+const toasts = (events) => {
+  let told = null;
+  const shown = [];
+  for (const [url, kind, cause] of events) {
+    const fresh = A.retold(told, url, kind, cause);
+    if (fresh) {
+      told = fresh;
+      shown.push(`${kind}:${cause}`);
+    }
+  }
+  return shown;
+};
+const attempt = [[DLF, "error", "csp"], [DLF, "error", "media"], [DLF, "error", "refused"]];
+console.log(JSON.stringify({
+  attempt: toasts(attempt),
+  reversed: toasts([...attempt].reverse()),
+  clicks: toasts([1, 2, 3, 4].flatMap(() => attempt)),
+  autoplay: toasts([[DLF, "blocked", "refused"], [DLF, "blocked", "refused"], ...attempt]),
+  stations: toasts([...attempt, [OTHER, "error", "media"], [OTHER, "error", "csp"]]),
+  origins: JSON.parse(process.argv[3]).map((url) => A.stationOrigins({url, via: []})[0]),
+  redirected: A.stationOrigins({url: DLF, via: ["https://*.rndfnk.com"]}),
+}));
+"""
+
+
+class TestRadioTrouble(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        command = ["node", "-e", PROBE, str(AMBIENCE), json.dumps([DLF, OTHER]), json.dumps(URLS)]
+        done = subprocess.run(command, capture_output=True, text=True, timeout=60, check=True)
+        cls.data = json.loads(done.stdout)
+
+    def test_a_blocked_redirect_and_its_media_error_toast_once(self):
+        self.assertEqual(self.data["attempt"], ["error:csp"])
+
+    def test_a_later_cause_replaces_a_lesser_one_but_never_the_other_way(self):
+        self.assertEqual(self.data["reversed"], ["error:refused", "error:media", "error:csp"])
+
+    def test_retries_through_clicks_stack_no_toast(self):
+        self.assertEqual(self.data["clicks"], ["error:csp"])
+
+    def test_each_failure_and_station_toasts_on_its_own(self):
+        self.assertEqual(self.data["autoplay"], ["blocked:refused", "error:csp"])
+        self.assertEqual(self.data["stations"], ["error:csp", "error:media", "error:csp"])
+
+    def test_the_page_computes_the_origins_the_server_puts_into_media_src(self):
+        self.assertEqual(self.data["origins"], [stream_origin(url) for url in URLS])
+        self.assertEqual(self.data["redirected"], ["https://st01.sslstream.dlf.de", "https://*.rndfnk.com"])
+
+
+if __name__ == "__main__":
+    unittest.main()