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>

functions/infra/scan_issues_dir.go

@@ -0,0 +1,62 @@
+package infra
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// ScanIssuesDir escanea el directorio root (dev/issues/) y devuelve todos los Issues
+// encontrados en *.md directos y en completed/*.md.
+// Si un archivo falla al parsearse, se emite un warning al log y se continua.
+// Los issues se devuelven ordenados por ID ascendente.
+func ScanIssuesDir(root string) ([]Issue, error) {
+	// Verificar que el directorio raiz existe.
+	if _, err := os.Stat(root); err != nil {
+		return nil, fmt.Errorf("scan_issues_dir: root dir %s: %w", root, err)
+	}
+
+	var issues []Issue
+
+	// Patterns a escanear: archivos directos y completed/
+	patterns := []string{
+		filepath.Join(root, "*.md"),
+		filepath.Join(root, "completed", "*.md"),
+	}
+
+	for _, pattern := range patterns {
+		matches, err := filepath.Glob(pattern)
+		if err != nil {
+			return nil, fmt.Errorf("scan_issues_dir: glob %s: %w", pattern, err)
+		}
+
+		for _, path := range matches {
+			// Saltar INDEX.md y README.md
+			base := filepath.Base(path)
+			if strings.EqualFold(base, "INDEX.md") || strings.EqualFold(base, "README.md") {
+				continue
+			}
+			// Verificar que es un archivo regular
+			info, err := os.Stat(path)
+			if err != nil || !info.Mode().IsRegular() {
+				continue
+			}
+
+			iss, _, err := ParseIssueMd(path)
+			if err != nil {
+				log.Printf("scan_issues_dir: warning: skip %s: %v", path, err)
+				continue
+			}
+			issues = append(issues, iss)
+		}
+	}
+
+	sort.Slice(issues, func(i, j int) bool {
+		return issues[i].ID < issues[j].ID
+	})
+
+	return issues, nil
+}