chore(registry): añadir uses_functions a consumidores reales (viz)

Auditoria del issue 0044: 9 archivos .md de cpp/functions/viz/ con
uses_functions actualizado. Resuelve dependencias detectadas via
#include: plot_static (consumido por bar_chart, histogram, line_plot,
pie_chart, scatter_plot), gl_loader, gl_framebuffer, gl_shader,
graph_force_layout, graph_renderer, graph_spatial_hash, orbit_camera,
sparkline y tokens.

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

cpp/functions/viz/histogram.md

@@ -8,7 +8,7 @@ purity: pure
 signature: "void histogram(const char* title, const float* values, int count, int bins = -1, float height = 200.0f)"
 description: "Histograma con bins automaticos, ejes lock (con AutoFit para bins dinamicos) y altura explicita"
 tags: [implot, chart, visualization, gpu, histogram, distribution, locked-axes]
-uses_functions: []
+uses_functions: ["plot_static_cpp_viz"]
 uses_types: []
 returns: []
 returns_optional: false
@@ -31,6 +31,7 @@ params:
   - name: height
     desc: "Altura del plot en pixeles (default 200). Explicita para evitar feedback loops con AutoResizeY"
 output: "Renderiza el histograma en el frame ImGui actual"
+notes: "scaffolding/demo en primitives_gallery"
 ---
 
 # histogram