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.

drm_outputs.py

@@ -189,33 +189,67 @@ def list_outputs() -> list[DrmOutput]:
     return outputs
 
 
+def _rank_wall(o: DrmOutput) -> tuple:
+    """Arc HDMI first, then any connected HDMI. Names shuffle across boots."""
+    return (
+        0 if o.connected else 1,
+        0 if o.driver == "xe" else 1,
+        0 if o.name.startswith("HDMI-A") else 1,
+        o.name,
+    )
+
+
+def pick_outputs(
+    all_outs: list[DrmOutput],
+    n: int = 3,
+    names: Optional[list[str]] = None,
+    connected_only: bool = False,
+) -> list[DrmOutput]:
+    """Choose DRM heads. Stale DISPLAY_CONNECTORS names must not bind a dead port
+    when a connected Arc HDMI is available — the wall has to stay lit."""
+    if names:
+        by_name: dict[str, list[DrmOutput]] = {}
+        for o in all_outs:
+            by_name.setdefault(o.name, []).append(o)
+        missing = [name for name in names if name not in by_name]
+        if missing:
+            have = sorted({o.name for o in all_outs})
+            raise KeyError(f"DRM connector {missing[0]!r} not found. Have: {have}")
+        picked: list[DrmOutput | None] = []
+        used: set[str] = set()
+        for name in names:
+            cands = sorted(by_name[name], key=_rank_wall)
+            chosen = next((o for o in cands if o.connected and o.sysfs not in used), None)
+            if chosen is None:
+                picked.append(None)
+            else:
+                used.add(chosen.sysfs)
+                picked.append(chosen)
+        fallback = sorted(
+            (o for o in all_outs if o.connected and o.sysfs not in used),
+            key=_rank_wall,
+        )
+        fi = 0
+        for i, o in enumerate(picked):
+            if o is None and fi < len(fallback):
+                picked[i] = fallback[fi]
+                used.add(fallback[fi].sysfs)
+                fi += 1
+        return [o for o in picked if o is not None]
+    connected = [o for o in all_outs if o.connected]
+    rest = [o for o in all_outs if not o.connected]
+    connected.sort(key=_rank_wall)
+    rest.sort(key=_rank_wall)
+    ordered = connected + ([] if connected_only else rest)
+    return ordered[:n]
+
+
 def select_outputs(
     n: int = 3,
     names: Optional[list[str]] = None,
     connected_only: bool = False,
 ) -> list[DrmOutput]:
-    all_outs = list_outputs()
-    if names:
-        by_name = {o.name: o for o in all_outs}
-        picked = []
-        for name in names:
-            if name not in by_name:
-                raise KeyError(f"DRM connector {name!r} not found. Have: {sorted(by_name)}")
-            picked.append(by_name[name])
-        return picked
-    connected = [o for o in all_outs if o.connected]
-    rest = [o for o in all_outs if not o.connected]
-    # Prefer the discrete GPU (xe / Arc) HDMI heads for a 3-display wall.
-    def rank(o: DrmOutput) -> tuple:
-        return (
-            0 if o.driver == "xe" else 1,
-            0 if o.name.startswith("HDMI-A") else 1,
-            o.name,
-        )
-    connected.sort(key=rank)
-    rest.sort(key=rank)
-    ordered = connected + ([] if connected_only else rest)
-    return ordered[:n]
+    return pick_outputs(list_outputs(), n=n, names=names, connected_only=connected_only)
 
 
 def format_outputs(outs: list[DrmOutput]) -> str: