Add Trace DASP preference to print protocol transactions to terminal

New checkbox in Preferences (default off). When enabled, every DASP
send (>>>) and receive (<<<) prints message type, seq/ack numbers,
payload size, and remote address to stdout.

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

main.py

@@ -1661,7 +1661,7 @@ def open_preferences_dialog():
 
     dialog = tk.Toplevel(window)
     dialog.title("Preferences")
-    dialog.geometry("470x290")
+    dialog.geometry("470x330")
     dialog.resizable(False, False)
     dialog.transient(window)
     dialog.grab_set()
@@ -1724,7 +1724,18 @@ def open_preferences_dialog():
         text="Yes",
         variable=var_timestamp
     )
-    chk_timestamp.grid(row=4, column=1, sticky="w", pady=(0, 15))
+    chk_timestamp.grid(row=4, column=1, sticky="w", pady=(0, 10))
+
+    lbl_trace = ttk.Label(frame_padded, text="Trace DASP to terminal?", anchor="w")
+    lbl_trace.grid(row=5, column=0, sticky="w", pady=(0, 15), padx=(0, 10))
+
+    var_trace_dasp = tk.BooleanVar(value=app_state.TRACE_DASP)
+    chk_trace_dasp = ttk.Checkbutton(
+        frame_padded,
+        text="Yes",
+        variable=var_trace_dasp
+    )
+    chk_trace_dasp.grid(row=5, column=1, sticky="w", pady=(0, 15))
 
     def apply_preferences():
         try:
@@ -1781,6 +1792,7 @@ def open_preferences_dialog():
             app_state.LEFT_PANE_WIDTH = pane_width
             app_state.GRID_SIZE = val
             app_state.ADD_TIMESTAMP = var_timestamp.get()
+            app_state.TRACE_DASP = var_trace_dasp.get()
             app_state.SEDONA_HOME = entry_home.get().strip()
 
             app_state.save_preferences()
@@ -1799,7 +1811,7 @@ def open_preferences_dialog():
             messagebox.showerror("Invalid Input", message, parent=dialog)
 
     btn_save_pref = ttk.Button(frame_padded, text="Apply Changes", command=apply_preferences)
-    btn_save_pref.grid(row=5, column=1, sticky="e")
+    btn_save_pref.grid(row=6, column=1, sticky="e")
 
     if not app_state.SEDONA_HOME:
         entry_home.focus_set()