Fix broadcast no-op: stop depending on orch object in LeafPane effects

The bug: clicking 📡 made the visual update (orange border) but typing
in a broadcasting pane only wrote to that pane — peers never received
the keystrokes.

Root cause: the orch context value (useMemo'd over activeLeafId,
distros, and the operation callbacks) is recreated every time
activeLeafId changes (i.e. every click). useEffect cleanups in
LeafPane that had `orch` in their deps fired their cleanup-then-setup
cycle on every click. The unmount-cleanup for paneId registration
ran `orch.registerPaneId(leaf.id, null)`, silently deleting paneIds
from App's paneIdByLeafRef map — so when broadcastFrom later walked
the tree looking up peers, the map returned undefined for every leaf
and the actual writeToPane calls never happened.

Fix: depend on the specific stable method references
(`orch.registerPaneId`, `orch.notify`, etc.) instead of the orch
object itself. The methods are all useCallback'd with stable deps
in App.tsx, so their references don't change across orch object
recreations — effect deps stay stable, no spurious cleanup.

Applied the same fix to all orch-using effects/callbacks in
LeafPane (commitLabel, pickDistro, onPaneClick, onPaneSpawned,
onXtermFocus, onTerminalInput, idle interval, paneId cleanup).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/layout/LeafPane.tsx

@@ -41,7 +41,7 @@ export default function LeafPane({ leaf }: { leaf: LeafNode }) {
     if (!editingLabel) return;
     orch.setLabel(leaf.id, labelDraft);
     setEditingLabel(false);
-  }, [editingLabel, orch, leaf.id, labelDraft]);
+  }, [editingLabel, orch.setLabel, leaf.id, labelDraft]);
   const cancelLabel = useCallback(() => setEditingLabel(false), []);
   const onLabelKey = useCallback(
     (e: KeyboardEvent<HTMLInputElement>) => {
@@ -67,7 +67,7 @@ export default function LeafPane({ leaf }: { leaf: LeafNode }) {
       setDistroOpen(false);
       if (d !== leaf.distro) orch.setDistro(leaf.id, d);
     },
-    [orch, leaf.id, leaf.distro],
+    [orch.setDistro, leaf.id, leaf.distro],
   );
   // Dismiss popover on outside click
   useEffect(() => {
@@ -95,14 +95,17 @@ export default function LeafPane({ leaf }: { leaf: LeafNode }) {
       }
     }, 1000);
     return () => clearInterval(id);
-  }, [leaf.label, leaf.distro, orch]);
+    // Depend on the stable notify function, not the whole orch object.
+    // orch is recreated every time activeLeafId/distros change; depending
+    // on it would tear down and rebuild this interval on every click.
+  }, [leaf.label, leaf.distro, orch.notify]);
 
   // ---- broadcast ---------------------------------------------------------
   const onTerminalInput = useCallback(
     (b64: string) => {
       if (isBroadcasting) orch.broadcastFrom(leaf.id, b64);
     },
-    [isBroadcasting, orch, leaf.id],
+    [isBroadcasting, orch.broadcastFrom, leaf.id],
   );
 
   // ---- focus / active highlighting ---------------------------------------
@@ -114,20 +117,26 @@ export default function LeafPane({ leaf }: { leaf: LeafNode }) {
 
   const onPaneClick = useCallback(() => {
     orch.setActive(leaf.id);
-  }, [orch, leaf.id]);
+  }, [orch.setActive, leaf.id]);
 
   const onPaneSpawned = useCallback(
     (paneId: number) => {
       orch.registerPaneId(leaf.id, paneId);
     },
-    [orch, leaf.id],
+    [orch.registerPaneId, leaf.id],
   );
-  // Unregister on unmount
+  // Unregister on TRUE unmount only — depending on `orch` here would
+  // delete the paneId from App's lookup on every activeLeafId change,
+  // which broke broadcast routing (peers found, but their paneIds
+  // had been silently removed from the map).
   useEffect(() => {
     return () => orch.registerPaneId(leaf.id, null);
-  }, [orch, leaf.id]);
+  }, [orch.registerPaneId, leaf.id]);
 
-  const onXtermFocus = useCallback(() => orch.setActive(leaf.id), [orch, leaf.id]);
+  const onXtermFocus = useCallback(
+    () => orch.setActive(leaf.id),
+    [orch.setActive, leaf.id],
+  );
 
   const onStatus = useCallback((msg: string, ok: boolean) => {
     setStatus(msg);