feat(viz): graph_types modelo extendido + EntityType/RelationType + flags (issue 0049e)

Extiende el modelo agnostico de graph_types.h para soportar shapes/iconos/
filtros/labels/streaming sin acoplar a backend. Migra el unico consumer
(demos_graph) en el mismo cambio.

- GraphNode v2: type_id + shape_override/color_override/size_override +
  flags (NF_PINNED/VISIBLE/SELECTED/HOVERED) + label_idx + user_data.
- GraphEdge v2: type_id + style_override + flags (EF_DIRECTED/VISIBLE).
- EntityType / RelationType: tablas en GraphData (types, rel_types).
- Helpers de resolucion (resolve_node_color/shape/size, resolve_edge_*)
  y constructores ergonomicos (graph_node, graph_edge, entity_type,
  relation_type) — sentinel-based para herencia automatica del tipo.
- graph_renderer v1.4: lee NF_VISIBLE / EF_VISIBLE, resuelve apariencia
  via override → EntityType → fallback indexado por type_id. Skipea
  aristas con endpoints invisibles. Shapes siguen pintandose como
  circulo (0049f cableara el dispatch real).
- graph_force_layout v1.2: pinned ahora vive en flags & NF_PINNED.
- graph_viewport v1.1: hover/seleccion publican NF_HOVERED/SELECTED en
  el grafo (clear-then-set). Drag usa NF_PINNED. Tooltip muestra Type/
  user_data en lugar de community/value/label.
- demos_graph: 8 EntityType (paleta antigua) + 1 RelationType. type_id
  por cluster. user_data = indice numerico del nodo. Apariencia visual
  identica al pre-cambio.
- test_graph_types.cpp: 12 casos cubriendo helpers, defaults, bitmask
  manipulation y resoluciones override-vs-EntityType. test_graph_edge_
  static actualizado al nuevo modelo (ya no tiene .color directo).
- 4 .md de tipos nuevos (graph_node, graph_edge, entity_type,
  relation_type) + GraphData v2.0 actualizado.

Tests: 31/31 ctest verdes (incluye test_visual golden).

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

cpp/functions/viz/graph_force_layout.cpp

@@ -265,7 +265,7 @@ float graph_force_layout_step(GraphData& graph, const ForceLayoutConfig& config)
         // stack local en pila, asi que es thread-safe.
         #pragma omp parallel for if(graph.node_count >= 1024) schedule(dynamic, 256)
         for (int i = 0; i < graph.node_count; ++i) {
-            if (graph.nodes[i].pinned) continue;
+            if (graph.nodes[i].flags & NF_PINNED) continue;
             quad_force(root,
                        graph.nodes[i].x, graph.nodes[i].y,
                        config.theta, config.repulsion, config.min_distance,
@@ -290,15 +290,15 @@ float graph_force_layout_step(GraphData& graph, const ForceLayoutConfig& config)
             float fx_e = force * dx / dist;
             float fy_e = force * dy / dist;
 
-            if (!graph.nodes[s].pinned) { fx_buf[s] += fx_e; fy_buf[s] += fy_e; }
-            if (!graph.nodes[t].pinned) { fx_buf[t] -= fx_e; fy_buf[t] -= fy_e; }
+            if (!(graph.nodes[s].flags & NF_PINNED)) { fx_buf[s] += fx_e; fy_buf[s] += fy_e; }
+            if (!(graph.nodes[t].flags & NF_PINNED)) { fx_buf[t] -= fx_e; fy_buf[t] -= fy_e; }
         }
 
         // ---- Gravity toward center (0,0) ----
         if (config.gravity != 0.0f) {
             #pragma omp parallel for if(graph.node_count >= 1024) schedule(static)
             for (int i = 0; i < graph.node_count; ++i) {
-                if (graph.nodes[i].pinned) continue;
+                if (graph.nodes[i].flags & NF_PINNED) continue;
                 fx_buf[i] -= config.gravity * graph.nodes[i].x;
                 fy_buf[i] -= config.gravity * graph.nodes[i].y;
             }
@@ -309,7 +309,7 @@ float graph_force_layout_step(GraphData& graph, const ForceLayoutConfig& config)
         #pragma omp parallel for if(graph.node_count >= 1024) schedule(static) reduction(+:total_energy)
         for (int i = 0; i < graph.node_count; ++i) {
             GraphNode& n = graph.nodes[i];
-            if (n.pinned) continue;
+            if (n.flags & NF_PINNED) continue;
 
             n.vx = n.vx * config.damping + fx_buf[i];
             n.vy = n.vy * config.damping + fy_buf[i];
@@ -332,7 +332,7 @@ float graph_force_layout_step(GraphData& graph, const ForceLayoutConfig& config)
 void graph_force_layout_reset(GraphData& graph, float spread) {
     for (int i = 0; i < graph.node_count; ++i) {
         GraphNode& n = graph.nodes[i];
-        if (n.pinned) continue;
+        if (n.flags & NF_PINNED) continue;
         // rand() produces [0, RAND_MAX]; map to [-spread, spread]
         n.x = spread * (2.0f * (float)rand() / (float)RAND_MAX - 1.0f);
         n.y = spread * (2.0f * (float)rand() / (float)RAND_MAX - 1.0f);
@@ -347,7 +347,7 @@ void graph_layout_circular(GraphData& graph, float radius) {
     const float two_pi = 6.28318530718f;
     for (int i = 0; i < graph.node_count; ++i) {
         GraphNode& n = graph.nodes[i];
-        if (n.pinned) continue;
+        if (n.flags & NF_PINNED) continue;
         float angle = two_pi * (float)i / (float)graph.node_count;
         n.x = radius * std::cos(angle);
         n.y = radius * std::sin(angle);
@@ -370,7 +370,7 @@ void graph_layout_grid(GraphData& graph, float spacing) {
     float oy = -0.5f * (rows - 1) * spacing;
     for (int i = 0; i < graph.node_count; ++i) {
         GraphNode& n = graph.nodes[i];
-        if (n.pinned) continue;
+        if (n.flags & NF_PINNED) continue;
         int col = i % cols;
         int row = i / cols;
         n.x = ox + col * spacing;