chore: scaffold skill_tree (issue 0109)

Initial scaffold via init_cpp_app_bash_pipelines:
- main.cpp con Tree + Inspector panels (placeholders)
- app.md con trio icon (tree-structure + #c026d3) + e2e_checks
- CMakeLists.txt via add_imgui_app
- appicon.ico generado con generate_app_icon_py_infra

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

app.md

@@ -0,0 +1,51 @@
+---
+name: skill_tree
+lang: cpp
+domain: tools
+description: "Mapa interactivo de issues+flows en anillos concentricos por estado, click para spawn agentes"
+tags: [dashboard, meta, imgui]
+icon:
+  phosphor: "tree-structure"
+  accent: "#c026d3"
+uses_functions: []
+uses_types: []
+framework: "imgui"
+entry_point: "main.cpp"
+dir_path: "apps/skill_tree"
+repo_url: "https://gitea.organic-machine.com/dataforge/skill_tree"
+e2e_checks:
+  - id: build
+    cmd: "cd cpp && cmake --build build --target skill_tree -j"
+    timeout_s: 300
+  - id: self_test
+    cmd: "./cpp/build/apps/skill_tree/skill_tree --self-test"
+    timeout_s: 30
+    severity: warning
+---
+
+# skill_tree
+
+Mapa interactivo de los issues + flows del registry en anillos concentricos por estado.
+Click en un nodo abre el panel `Inspector` con su Definition of Done y las funciones
+del registry asociadas. Dos botones por nodo:
+
+- **Generate ideas** (`claude -p`) → escribe a `idea_drafts` para revision manual.
+- **Run autonomous-task** (`fn-orquestador`) → spawn subagente en sandbox `auto/<issue>`.
+
+Roadmap: issue 0109. Diseno completo en el frontmatter del epic.
+
+## Build
+
+```bash
+cd cpp && cmake --build build --target skill_tree -j
+```
+
+## Run
+
+```bash
+./cpp/build/apps/skill_tree/skill_tree
+```
+
+## Estado
+
+MVP fase A — sub-issue 0109a: shell + parsers issues/flows. Sin render de grafo todavia.