feat: point the fleet at wss LiveKit room uwh-telhai

Publish and subscribe over wss://livekit.uni-wh.de:7800 and refuse
cleartext ws://. Conference room is uwh-telhai. Includes the uncommitted
encoded H.264 publish path, Rally hairpin, and KMS wall overlay.

tests/test_h264_fifo.py

@@ -0,0 +1,30 @@
+import os
+import stat
+
+from h264_fifo import hold_fifo
+
+
+def test_hold_fifo_creates_rdwr_pipe(tmp_path):
+    path = str(tmp_path / "cam-01.h264")
+    fd = hold_fifo(path)
+    try:
+        st = os.stat(path)
+        assert stat.S_ISFIFO(st.st_mode)
+        os.write(fd, b"\x00\x01")
+        assert os.read(fd, 2) == b"\x00\x01"
+    finally:
+        os.close(fd)
+
+
+def test_hold_fifo_does_not_replace_existing_fifo(tmp_path):
+    path = str(tmp_path / "cam-02.h264")
+    a = hold_fifo(path)
+    ino = os.stat(path).st_ino
+    b = hold_fifo(path)
+    try:
+        assert os.stat(path).st_ino == ino
+        os.write(a, b"ab")
+        assert os.read(b, 2) == b"ab"
+    finally:
+        os.close(a)
+        os.close(b)