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>

types/infra/flow_go_infra.md

@@ -0,0 +1,38 @@
+---
+name: flow
+lang: go
+domain: infra
+version: "0.1.0"
+algebraic: product
+definition: |
+  type Flow struct {
+      ID       string   `yaml:"id"`
+      Title    string   `yaml:"title,omitempty"`
+      Status   string   `yaml:"status,omitempty"`
+      Kind     string   `yaml:"kind,omitempty"`
+      Tags     []string `yaml:"tags,omitempty"`
+      Name     string   `yaml:"name,omitempty"`
+      Priority string   `yaml:"priority,omitempty"`
+      FilePath string   `yaml:"-"`
+      MtimeNs  int64    `yaml:"-"`
+  }
+description: "Frontmatter YAML de un archivo dev/flows/*.md. Campos de runtime (FilePath, MtimeNs) no se serializan en YAML."
+tags: [flow, frontmatter, yaml, kanban, dev-ux, registry]
+uses_types: []
+file_path: "functions/infra/flow_type.go"
+---
+
+## Ejemplo
+
+```go
+f := infra.Flow{
+    ID:     "0001",
+    Name:   "hn-top-stories",
+    Status: "pending",
+    Tags:   []string{"scraping", "news"},
+}
+```
+
+## Notas
+
+Producido por `scan_flows_dir_go_infra`. Los flows del registry usan campos variados en su frontmatter — el struct cubre el subconjunto comun: id/name/title/status/kind/tags/priority. Campos desconocidos se ignoran silenciosamente por yaml.Unmarshal.

types/infra/fs_event_go_infra.md

@@ -0,0 +1,30 @@
+---
+name: fs_event
+lang: go
+domain: infra
+version: "0.1.0"
+algebraic: product
+definition: |
+  type FsEvent struct {
+      Path string
+      Op   string // "create" | "write" | "remove" | "rename"
+  }
+description: "Evento del watcher de sistema de archivos. Op es uno de: create, write, remove, rename."
+tags: [watcher, fsnotify, event, filesystem, kanban, dev-ux]
+uses_types: []
+file_path: "functions/infra/fs_event_type.go"
+---
+
+## Ejemplo
+
+```go
+// Recibido desde el canal de watch_dir_fsnotify_go_infra:
+ev := infra.FsEvent{
+    Path: "/home/lucas/fn_registry/dev/issues/0130a-kanban-cpp-v2-parser.md",
+    Op:   "write",
+}
+```
+
+## Notas
+
+Producido por `watch_dir_fsnotify_go_infra`. El canal emite un evento por archivo afectado tras el debounce de 200ms. Si se producen multiples operaciones sobre el mismo path en la ventana de debounce, se emite solo la ultima operacion.

types/infra/issue_go_infra.md

@@ -0,0 +1,51 @@
+---
+name: issue
+lang: go
+domain: infra
+version: "0.1.0"
+algebraic: product
+definition: |
+  type Issue struct {
+      ID       string   `yaml:"id"`
+      Title    string   `yaml:"title"`
+      Status   string   `yaml:"status"`
+      Type     string   `yaml:"type"`
+      Domain   []string `yaml:"domain"`
+      Scope    string   `yaml:"scope"`
+      Priority string   `yaml:"priority"`
+      Depends  []string `yaml:"depends"`
+      Blocks   []string `yaml:"blocks"`
+      Related  []string `yaml:"related"`
+      Tags     []string `yaml:"tags"`
+      Flow     string   `yaml:"flow,omitempty"`
+      Created  string   `yaml:"created"`
+      Updated  string   `yaml:"updated"`
+      FilePath string   `yaml:"-"`
+      MtimeNs  int64    `yaml:"-"`
+      Completed bool    `yaml:"-"`
+  }
+description: "Frontmatter YAML de un archivo dev/issues/*.md. Campos de runtime (FilePath, MtimeNs, Completed) no se serializan en YAML."
+tags: [issue, frontmatter, yaml, kanban, dev-ux, registry]
+uses_types: []
+file_path: "functions/infra/issue_type.go"
+---
+
+## Ejemplo
+
+```go
+iss := infra.Issue{
+    ID:       "0130",
+    Title:    "Kanban C++ v2",
+    Status:   "pendiente",
+    Priority: "alta",
+    Domain:   []string{"cpp-stack", "apps-infra"},
+    Scope:    "multi-app",
+    Tags:     []string{"kanban", "cpp"},
+    Created:  "2026-05-22",
+    Updated:  "2026-05-22",
+}
+```
+
+## Notas
+
+Producido por `parse_issue_md_go_infra`. Los campos `Depends`, `Blocks`, `Related`, `Tags`, `Domain` se deserializan como `[]string` — si el YAML los omite, quedan como slice vacio (no nil). `Completed` se deduce del path (contiene `/completed/`), no del frontmatter.