docs(guides): fix stale src/models.py refs + line-number drift across 11 guides

Sweep of the per-source-file guides + Readme.md for stale references
to src/models.py as the data model home. models.py is now a ~1.5KB
re-export shim per module_taxonomy_refactor_20260627; dataclasses
moved to src/mma.py, src/project_files.py, src/type_aliases.py,
src/mcp_tool_specs.py, src/result_types.py, src/context_presets.py,
src/workspace_manager.py, src/personas.py.

- guide_gui_2.md: _gui_func line 754->1062; render_main_interface
  line 1259->1898.
- python.md §10 exemption table: App gui_2.py:307->314; AppController
  795->801; RAGEngine 123->125; HookServer 856->941;
  HookServerInstance 130->171; HookHandler 155->208;
  WebSocketServer 908->993.
- guide_multi_agent_conductor.md: Ticket now in src/mma.py (not
  models.py); ConductorEngine 116+->112+; WorkerPool 50-114->52-110.
- guide_agent_memory_dimensions.md: FileItem ref models.py:510-559
  -> src/project_files.py.
- guide_context_aggregation.md: FileItem + ContextPreset refs ->
  src/project_files.py + src/context_presets.py; ai_client _send_*
  count 5->8.
- guide_discussions.md: parse_history_entries now in src/mma.py;
  ContextPreset/FileItem cross-refs updated.
- guide_personas.md: Persona now in src/personas.py; import example
  updated.
- guide_rag.md: RAGConfig now in src/mcp_client.py.
- guide_workspace_profiles.md: WorkspaceProfile now in
  src/workspace_manager.py.
- guide_mma.md: Data Structures section notes src/mma.py as the live
  location.
- Readme.md: MMA Engine + Data Models rows updated for the
  models.py shim reality + 8 providers + mma_exec deprecation.
- guide_ai_client.md: '5 provider SDKs'->8 (added note); PROVIDERS
  line 56->62; __getattr__ re-export line 261->31; provider
  switching examples use real registered model names (claude-sonnet-
  4-5, MiniMax-M2, gemini-2.5-flash, qwen-plus, grok-2, llama-3.1);
  _provider union lists all 8 providers.

docs/guide_gui_2.md

@@ -100,7 +100,7 @@ The App holds dozens of state attributes. The most important:
 | `self._tool_log` | `deque` | Tool call log |
 | `show_command_palette` | `bool` | Command palette visibility |
 
-### Render Entry Point: `_gui_func` (line 754)
+### Render Entry Point: `_gui_func` (line 1062)
 
 The main render loop, called by imgui-bundle's Hello ImGui runner every frame:
 
@@ -130,7 +130,7 @@ def _gui_func(self) -> None:
     render_error_tint(self)
 ```
 
-### `render_main_interface` (line 1259)
+### `render_main_interface` (line 1898)
 
 The "main content" renderer. Iterates over the major panels and calls the right render function for each: