feat(primitives_gallery): demos individuales para wave 1 + 5 primitivos viz/core

Cobertura del catalogo visual:
- text_editor (Wave 1, 0025): demo solo del editor con dropdown GLSL/SQL/Cpp/Generic.
- file_watcher (Wave 1, 0025): demo solo del watcher con boton touch + log.
- gl_texture_load (Wave 1, 0026): ya tenia demo (Gfx).
- process_runner: tarea simulada en background con spinner.
- candlestick: 30 dias OHLC sintetico.
- gauge: 3 indicadores con sliders (CPU/MEM/GPU).
- heatmap: gaussiana 12x12.
- table_view: 6 funciones del registry como muestra.

El demo combinado anterior (text_editor + watcher) se separa en dos para
que cada entry del sidebar exhiba un solo primitivo. Mas claro y mas
indexable.

Total entries en gallery: 26 (antes 23).

cpp/apps/primitives_gallery/CMakeLists.txt

@@ -7,6 +7,7 @@ add_imgui_app(primitives_gallery
     demos_gfx.cpp
     demos_text_editor.cpp
     demos_gl_texture.cpp
+    demos_extras.cpp
     # text_editor + file_watcher (issue 0025)
     ${CMAKE_SOURCE_DIR}/functions/core/text_editor.cpp
     ${CMAKE_SOURCE_DIR}/functions/core/file_watcher.cpp
@@ -34,6 +35,10 @@ add_imgui_app(primitives_gallery
     ${CMAKE_SOURCE_DIR}/functions/viz/scatter_plot.cpp
     ${CMAKE_SOURCE_DIR}/functions/viz/histogram.cpp
     ${CMAKE_SOURCE_DIR}/functions/viz/sparkline.cpp
+    ${CMAKE_SOURCE_DIR}/functions/viz/candlestick.cpp
+    ${CMAKE_SOURCE_DIR}/functions/viz/gauge.cpp
+    ${CMAKE_SOURCE_DIR}/functions/viz/heatmap.cpp
+    ${CMAKE_SOURCE_DIR}/functions/viz/table_view.cpp
     # Graph stack (instanced GPU + Barnes-Hut + spatial hash)
     ${CMAKE_SOURCE_DIR}/functions/viz/graph_types.cpp
     ${CMAKE_SOURCE_DIR}/functions/viz/graph_renderer.cpp