feat(0130): kanban_cpp v2 — backend Go + 5 registry parser fns + epic/sub-issues

Registry (issue 0130a):
- 5 fns infra: parse_issue_md, write_issue_md, scan_issues_dir,
  scan_flows_dir, watch_dir_fsnotify
- 3 tipos: Issue, Flow, FsEvent
- Tests round-trip + scan reales + watcher fsnotify (all PASS)
- Capability group 'kanban' nuevo (docs/capabilities/kanban.md)

Apps:
- apps/kanban_cpp/ (sub-repo) — frontend ImGui: board drag-drop,
  flows, filters, detail con CSV editors
- apps/kanban_cpp/backend/ — Go service port 8487: REST + SSE +
  fsnotify watcher, parser bidireccional MD<->SQLite cache

Issues:
- dev/issues/0130-kanban-cpp-v2.md (epic)
- 0130a parser, 0130b backend, 0130c frontend

CMakeLists.txt: add_subdirectory apps/kanban_cpp (registrado por
init_cpp_app scaffolder).

End-to-end verde: backend devuelve 189 issues + 9 flows; PATCH a
/api/issues/{id} reescribe .md (solo frontmatter, body intacto);
frontend --self-test exit 0; tests Go infra 5/5 PASS.

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

docs/capabilities/INDEX.md

@@ -40,6 +40,7 @@ Indice de grupos de capacidades del registry. Cada grupo agrupa >=3 funciones qu
 | [cpp-dashboard-viz](cpp-dashboard-viz.md) | 10 | Primitivas C++ ImGui para dashboards: kpi_card, sparkline, line/bar/scatter/pie/heatmap/histogram, panel containers |
 | [agents](agents.md) | 3 | Orquestar agentes Claude headless en git worktrees: launch, cleanup, DoD evidence schema audit |
 | [backends](backends.md) | — | Stacks backend (Go net/http+SQLite default, MCP, mautrix, bubbletea, httpx, docker-compose): decision tree + esqueleto canonico + funciones del registry a componer |
+| [kanban](kanban.md) | 5 | Parser/writer/scanner/watcher de dev/issues/ y dev/flows/: base del backend kanban_cpp v2 |
 
 ## Como anadir grupo