Auto-open Kit Manager when file has kits without checksums

When a SAX file is opened and any declared kit is missing a checksum,
the Kit Manager panel opens automatically and the palette stays empty
until the checksums are resolved.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main.py

@@ -1578,11 +1578,21 @@ def on_tree_filled():
     if app_state.current_file_path != _history_file_path:
         _history_file_path = app_state.current_file_path
         reset_view_history()
+
+        if _schema_has_incomplete_checksums():
+            show_kits()
     else:
         _prune_view_history()
         update_history_controls()
 
 
+def _schema_has_incomplete_checksums():
+    """Whether any declared kit is missing a checksum."""
+    if not app_state.active_schema_kits:
+        return False
+    return any(cs is None for cs in app_state.active_schema_kits.values())
+
+
 # --- Dialogs ---
 
 def open_preferences_dialog():
@@ -2105,8 +2115,11 @@ def refresh_palette_kits():
     global palette_kit_names
 
     palette.invalidate()
-    declared = list(app_state.active_schema_kits.keys())
-    palette_kit_names = sorted(declared)
+
+    if _schema_has_incomplete_checksums():
+        palette_kit_names = []
+    else:
+        palette_kit_names = sorted(app_state.active_schema_kits.keys())
 
     labels = []
     for kit_name in palette_kit_names: