feat(viz): graph_sources lector operations.db + streaming (issue 0049g)

- graph_load_from_operations: SQLite read-only, schema-detect (type_ref/type,
  from_entity/source, to_entity/target, name/type, weight, updated_at).
- 16-color indigo palette por hash FNV1a32 del nombre de tipo. user_data
  por nodo es FNV1a64(entity.id) — deterministico entre cargas.
- Label pool interno: metadata.name (JSON simple) > entities.name > id.
- graph_free libera nodes/edges/types/rel_types/labels/strdup'd names via
  arena_map (GraphData* -> arena).
- Streaming pull-based con tiebreak (updated_at, id) y crecimiento x2 de
  capacidad. Tipos nuevos descubiertos en stream se anaden a types.
- Tests: fixture in-memory (3 entity types, 2 rel types, 10 entities,
  15 relations) + smoke contra apps/script_navegador/operations.db.
- Issue movido a completed/.

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

cpp/tests/CMakeLists.txt

@@ -74,6 +74,12 @@ add_fn_test(test_graph_edge_static test_graph_edge_static.cpp
 add_fn_test(test_graph_types test_graph_types.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/graph_types.cpp)
 
+# --- Issue 0049g — graph_sources: lector de operations.db ------------------
+add_fn_test(test_graph_sources test_graph_sources.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/graph_sources.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/graph_types.cpp)
+target_link_libraries(test_graph_sources PRIVATE SQLite::SQLite3)
+
 # --- Issue 0049f — atlas de iconos Tabler para graph_renderer ---------------
 # graph_icons.cpp incluye gl_loader.h y referencia gl* — el atlas se puede
 # construir sin contexto via FN_GRAPH_ICONS_SKIP_GL=1 (set por el test), pero