feat: graph_explorer app — agnostic operations.db viewer (issue 0049k)

App C++ ImGui que abre cualquier operations.db del registry y lo visualiza
como grafo con shapes/iconos/layouts/filtros/labels.

Composicion del registry:
- viz/graph_renderer + graph_force_layout(_gpu) + graph_layouts +
  graph_viewport + graph_labels + graph_icons + graph_sources
- core: toolbar, modal_dialog, select, text_input, tree_view, page_header,
  fullscreen_window, button, badge, empty_state

Capas:
- data.{h,cpp}    — dispatcher GraphLoadFn (operations hoy; json/graphml manana).
- types_registry.{h,cpp} — parser YAML minimal + tabler_codepoint_by_name +
  apply_types_yaml + IconAtlas builder.
- views.{h,cpp}   — Toolbar, Legend, Inspector, Stats, modal Filters/Open.
- layout_store.{h,cpp} — graph_explorer.db SQLite con tabla layouts(graph_hash,
  node_id, x, y, pinned, updated_at). UPSERT por nodo.
- main.cpp        — CLI (--input/--types/--layout) + fn::run_app + bucle
  force layout (CPU/GPU toggle) + render con 3 columnas (Legend / Viewport /
  Inspector+Stats).

examples/types.yaml: 10 entidades OSINT (Person/Email/Domain/Phone/Org/IBAN/
Account/Document/Address/Url) + 5 relaciones (owns/knows/located_in/
transfers_to/member_of) con shapes Tabler reales.

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

examples/types.yaml

@@ -0,0 +1,77 @@
+# Ejemplo OSINT — tipos comunes en investigacion de entidades.
+# Color como "#RRGGBB" (con o sin alpha "#RRGGBBAA").
+# Shapes: circle | square | diamond | hex | triangle | rounded_square
+# Iconos: nombres ti-* mapeados en types_registry.cpp::tabler_codepoint_by_name
+# Estilos de relacion: solid | dashed | dotted
+
+entities:
+  - name: Person
+    color: "#5B8DEF"
+    shape: circle
+    icon: ti-user
+
+  - name: Email
+    color: "#58CA8C"
+    shape: square
+    icon: ti-mail
+
+  - name: Domain
+    color: "#F4B860"
+    shape: diamond
+    icon: ti-world
+
+  - name: Phone
+    color: "#E36AC0"
+    shape: hex
+    icon: ti-phone
+
+  - name: Org
+    color: "#C780E8"
+    shape: triangle
+    icon: ti-building
+
+  - name: IBAN
+    color: "#52CDF2"
+    shape: rounded_square
+    icon: ti-building-bank
+
+  - name: Account
+    color: "#7FD3A0"
+    shape: rounded_square
+    icon: ti-id
+
+  - name: Document
+    color: "#C9C9C9"
+    shape: square
+    icon: ti-file
+
+  - name: Address
+    color: "#FFB870"
+    shape: diamond
+    icon: ti-map-pin
+
+  - name: Url
+    color: "#89E0FC"
+    shape: hex
+    icon: ti-link
+
+relations:
+  - name: owns
+    color: "#888888"
+    style: solid
+
+  - name: knows
+    color: "#AAAAAA"
+    style: solid
+
+  - name: located_in
+    color: "#FFB870"
+    style: dashed
+
+  - name: transfers_to
+    color: "#52CDF2"
+    style: dotted
+
+  - name: member_of
+    color: "#C780E8"
+    style: dashed