fix(gui): Final monolithic stabilization and UI polish

- Restore monolithic architecture in gui_2.py to fix test compatibility.
- Implement full-width horizontal expansion for Markdown tables in discussion entries.
- Re-implement layered role-based tints using draw_list channels.
- Standardize Text Viewer docking ID to '###Text_Viewer_Unified'.
- Fix MiniMax compression routing and base URL.
- Fully restore missing theme_2.py definitions.

src/imgui_scopes.py

@@ -39,7 +39,8 @@ class _ScopeId:
   """
   self._id = str_id
  def __enter__(self):
-  # Always pass string to avoid access violations with certain types in imgui-bundle
+  # Use explicit conversion to avoid any possible nanobind ambiguity
+  # and access violations. String IDs are the most stable in this binding.
   imgui.push_id(str(self._id))
  def __exit__(self, *args):
   imgui.pop_id()