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.

usb_ids.py

@@ -0,0 +1,62 @@
+"""USB identities for the fleet vs the (future) speaker Rally."""
+from __future__ import annotations
+
+from pathlib import Path
+
+LOGITECH_VID = 0x046D
+# HD Pro C920 (this fleet) and the older 082d id.
+C920_PIDS = frozenset({0x08E5, 0x082D})
+# Logi Rally Camera 0881; Rally Bar / Mini / Huddle variants.
+RALLY_PIDS = frozenset({0x0881, 0x087C, 0x089B, 0x08D3})
+RALLY_IDENTITY = "rally"
+# Huddly IQ on the PCH/Dante hub — not a cam-NN slot.
+HUDDLY_VID = 0x2BD9
+HUDDLY_PIDS = frozenset({0x0021})
+
+
+def usb_vid_pid_from_sysfs(sysfs_device: str) -> tuple[int, int] | None:
+    p = Path(sysfs_device)
+    for _ in range(12):
+        vend = p / "idVendor"
+        prod = p / "idProduct"
+        if vend.is_file() and prod.is_file():
+            try:
+                return int(vend.read_text().strip(), 16), int(prod.read_text().strip(), 16)
+            except ValueError:
+                return None
+        if str(p).startswith("/sys/devices"):
+            p = p.parent
+        else:
+            return None
+    return None
+
+
+def usb_vid_pid_of_video_node(video_node: str) -> tuple[int, int] | None:
+    link = Path(f"/sys/class/video4linux/{Path(video_node).name}/device")
+    try:
+        real = str(link.resolve())
+    except OSError:
+        return None
+    return usb_vid_pid_from_sysfs(real)
+
+
+def is_c920_pid(pid: int) -> bool:
+    return int(pid) in C920_PIDS
+
+
+def is_huddly_iq(vid: int, pid: int) -> bool:
+    return int(vid) == HUDDLY_VID and int(pid) in HUDDLY_PIDS
+
+
+def is_fleet_video(vid: int, pid: int) -> bool:
+    """True only for the 20 C920s. Rally, Huddly IQ, etc. stay out of cam-NN."""
+    return int(vid) == LOGITECH_VID and int(pid) in C920_PIDS
+
+
+def is_rally_pid(pid: int) -> bool:
+    return int(pid) in RALLY_PIDS
+
+
+def looks_like_rally_name(name: str) -> bool:
+    n = (name or "").lower()
+    return "rally" in n