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/graph_renderer.md

@@ -8,7 +8,7 @@ purity: impure
 signature: "GraphRenderer* graph_renderer_create(int width, int height, const GraphRendererConfig& config)"
 description: "Renderer GPU de grafos con instanced rendering a FBO, compatible con ImGui::Image para visualizacion de grafos grandes"
 tags: [graph, renderer, opengl, gpu, instanced, fbo, visualization]
-uses_functions: []
+uses_functions: ["gl_loader_cpp_gfx"]
 uses_types: ["GraphData_cpp_viz"]
 returns: []
 returns_optional: false