feat(skill_tree): Launch workflow via agent_runner_api + feature flag legacy_claude_fix (issue 0116)

- dev/feature_flags.json: anade 'legacy_claude_fix' (enabled:false,
  issue 0116). Default OFF — el flujo canonico ahora es 'Launch workflow'
  (POST :8486/api/runs); el boton 'Claude fix' legacy (terminal externa +
  claude --dangerously-skip-permissions) solo se renderiza si se activa
  el flag.
- Mueve dev/issues/0116-skill-tree-launch-workflow.md a completed/.

El codigo C++ del boton vive en el sub-repo dataforge/skill_tree
(apps/skill_tree, commit 9ee3be8).

dev/feature_flags.json

@@ -17,5 +17,12 @@
     "description": "Visor de grafos GPU-accelerated agnostico del backend (graph_explorer en projects/osint_graph) + sistema de renderer extendido (shapes, iconos Tabler, edge styles, flechas, layouts force-GPU/radial/hierarchical, labels con politica). Activado al cerrar 0049k.",
     "added": "2026-04-29",
     "enabled_at": "2026-04-30"
+  },
+  "legacy_claude_fix": {
+    "enabled": false,
+    "issue": "0116",
+    "description": "Mostrar boton 'Claude fix' (terminal externa + claude --dangerously-skip-permissions) en skill_tree. Default OFF tras 0116 — el flujo canonico es 'Launch workflow' (POST :8486/api/runs).",
+    "added": "2026-05-18",
+    "enabled_at": null
   }
 }