Drag links out of slots on the wiresheet; hide @palette=false types

Hovering a slot row highlights the half under the pointer and shows a
direction cursor. Pressing on a slot drags a rubber band; dropping on
another slot links them, dropping on a title bar opens the Link dialog
with the dragged slot preselected, and a no-entry cursor marks a slot
that would refuse the link. A right click that never moves still opens
the context menu.

The palette now leaves out types whose facets carry @palette=false, and
kits with nothing placeable left.

Also points the default device host at 192.168.1.251.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

palette.py

@@ -227,11 +227,25 @@ def _is_component(qualified_name, seen=None):
     return result
 
 
+def _hidden_from_palette(type_element):
+    """True when the type's own facets carry @palette=false.
+
+    Only the type-level <facets> counts; slots have <facets> of their own nested deeper.
+    """
+    facets = type_element.find("facets")
+    if facets is None:
+        return False
+    for facet in facets.findall("bool"):
+        if facet.get("name") == "palette" and facet.get("val") == "false":
+            return True
+    return False
+
+
 def list_component_types(kit_name):
     """Concrete component types in a kit, as (type name, base) pairs.
 
-    Primitives (no base) and abstract types (the 'a' flag) are left out — neither can be
-    placed in an application.
+    Primitives (no base), abstract types (the 'a' flag) and types marked @palette=false
+    are left out — none of them belong in the palette.
     """
     _, types = _load_kit(kit_name)
 
@@ -239,6 +253,8 @@ def list_component_types(kit_name):
     for type_name, type_element in types.items():
         if "a" in (type_element.get("flags") or ""):
             continue
+        if _hidden_from_palette(type_element):
+            continue
         if not _is_component(f"{kit_name}::{type_name}"):
             continue
         entries.append((type_name, type_element.get("base") or ""))