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.

audio_gst.py

@@ -0,0 +1,40 @@
+"""GStreamer ALSA capture graphs for the shared audio daemon."""
+from __future__ import annotations
+
+import shutil
+
+GST_LAUNCH = shutil.which("gst-launch-1.0") or "gst-launch-1.0"
+GST_GROUP_SIZE = 5
+
+
+def shared_audio_cmd(
+    cameras: list[tuple[str, int]],
+    rate: int,
+    fds: list[int],
+) -> list[str]:
+    if len(cameras) != len(fds):
+        raise ValueError("cameras and fds length mismatch")
+    cmd: list[str] = [GST_LAUNCH, "-q"]
+    caps = f"audio/x-raw,format=S16LE,rate={int(rate)},channels=2"
+    for (_ident, card), fd in zip(cameras, fds):
+        cmd += [
+            "alsasrc", f"device=hw:{int(card)},0", "do-timestamp=false",
+            "!", caps,
+            "!", "queue", "max-size-buffers=2", "max-size-bytes=0",
+            "max-size-time=0", "leaky=downstream",
+            "!", "fdsink", f"fd={int(fd)}", "sync=false",
+        ]
+    return cmd
+
+
+def grouped_audio(
+    cameras: list[tuple[str, int]],
+    fds: list[int],
+    group_size: int = GST_GROUP_SIZE,
+) -> list[tuple[list[tuple[str, int]], list[int]]]:
+    if group_size < 1:
+        raise ValueError("group_size must be >= 1")
+    out = []
+    for i in range(0, len(cameras), group_size):
+        out.append((cameras[i:i + group_size], fds[i:i + group_size]))
+    return out