Preferences: lazy loading on connect, on by default

Off reads the whole app from app.sab when connecting. Read at each connect, so a
change takes effect on the next one.

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

app_state.py

@@ -8,7 +8,7 @@ so later rebinding would only ever be seen by the module that did it.
 import configparser
 import os
 
-VERSION = "0.0.0.170"
+VERSION = "0.0.0.171"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True
@@ -118,6 +118,7 @@ def load_preferences():
     left_pane_width = DEFAULT_LEFT_PANE_WIDTH
     sedona_home = ""
     trace_dasp = False
+    lazy_loading = True
 
     if os.path.exists(PROPERTIES_FILE):
         try:
@@ -130,6 +131,7 @@ def load_preferences():
             )
             sedona_home = config.get("Editor", "sedona.home", fallback="").strip()
             trace_dasp = config.getboolean("Editor", "trace_dasp", fallback=False)
+            lazy_loading = config.getboolean("Editor", "lazy_loading", fallback=True)
         except Exception:
             pass
     else:
@@ -150,7 +152,8 @@ def load_preferences():
     left_pane_width = max(
         MIN_ALLOWED_LEFT_PANE_WIDTH, min(MAX_ALLOWED_LEFT_PANE_WIDTH, left_pane_width)
     )
-    return sedona_home, grid_size, add_timestamp, box_width, left_pane_width, trace_dasp
+    return (sedona_home, grid_size, add_timestamp, box_width, left_pane_width, trace_dasp,
+            lazy_loading)
 
 
 def save_preferences():
@@ -170,6 +173,7 @@ def save_preferences():
         "box_width": str(BOX_WIDTH),
         "left_pane_width": str(LEFT_PANE_WIDTH),
         "trace_dasp": str(TRACE_DASP),
+        "lazy_loading": str(LAZY_LOADING),
     }
     with open(PROPERTIES_FILE, "w") as configfile:
         config.write(configfile)
@@ -259,5 +263,8 @@ def base_window_title_live():
     return f"Sedona Live Editor [v{VERSION}] — {device_host}:{device_port}"
 
 
-SEDONA_HOME, GRID_SIZE, ADD_TIMESTAMP, BOX_WIDTH, LEFT_PANE_WIDTH, TRACE_DASP = load_preferences()
+# LAZY_LOADING: on connect, read components as folders are opened (True) or the whole
+# app from app.sab first (False). Read at each connect, so a change takes effect on the next.
+(SEDONA_HOME, GRID_SIZE, ADD_TIMESTAMP, BOX_WIDTH, LEFT_PANE_WIDTH, TRACE_DASP,
+ LAZY_LOADING) = load_preferences()
 LAST_PALETTE_KIT = load_last_palette_kit()