feat(0013): wire extract_panel into main + CMakeLists + app.md

- main.cpp: registra panel_extract en g_panels[], llama
  extract_panel_init tras jobs_init y extract_panel_shutdown en el
  cleanup, anade extract_panel_render(g_app) al render.
- CMakeLists.txt: anade extract_panel.cpp al target.
- app.md: declara extract_iocs_py_cybersecurity y
  extract_graph_hybrid_py_pipelines en uses_functions (regla
  uses_functions.md).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CMakeLists.txt

@@ -27,6 +27,7 @@ add_imgui_app(graph_explorer
     jobs.cpp
     enrichers.cpp
     chat.cpp
+    extract_panel.cpp
     # --- viz ---
     ${FN_CPP_ROOT_DIR}/functions/viz/graph_renderer.cpp
     ${FN_CPP_ROOT_DIR}/functions/viz/graph_force_layout.cpp