Move Theme tab to first position in interactive editor

Theme affects all subsequent plots globally, so it deserves the most
prominent position to help users set it before making other edits.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: brycewang-stanford

src/statspai/plots/_jupyter_editor.py

@@ -1270,25 +1270,24 @@ def _live_code_update(figure):
             '<div style="padding:20px; color:#999; text-align:center">'
             'Loading...</div>')]),
     }
-    _tab_loaded = {0: True, 1: False, 2: False, 3: False, 4: False}
+    _tab_loaded = {0: True, 1: True, 2: False, 3: False, 4: False}
     _real_tabs = {
-        1: style_container,
-        2: layout_tab,
-        3: theme_tab,
+        2: style_container,
+        3: layout_tab,
         4: code_tab,
     }
 
     tabs = widgets.Tab(children=[
+        theme_tab,
         text_tab,
-        _lazy_placeholders[1],
         _lazy_placeholders[2],
         _lazy_placeholders[3],
         _lazy_placeholders[4],
     ])
-    tabs.set_title(0, 'Text')
-    tabs.set_title(1, 'Style')
-    tabs.set_title(2, 'Layout')
-    tabs.set_title(3, 'Theme')
+    tabs.set_title(0, 'Theme')
+    tabs.set_title(1, 'Text')
+    tabs.set_title(2, 'Style')
+    tabs.set_title(3, 'Layout')
     tabs.set_title(4, 'Export')
 
     def _on_tab_switch(change):