feat(infra): audit_dod_schema + fn doctor dod (issue 0114)

Adds AuditDodSchema(issuesDir, flowsDir) which scans dev/issues/ and
dev/flows/ frontmatter for the new optional dod_evidence_schema: block.
Validates id uniqueness, kind in {screenshot,log,url,cmd}, expected
non-empty and required bool (default true). Tolerant to malformed YAML
and missing block.

Wires it into fn doctor dod with human-readable caveman output and
--json support.

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

cmd/fn/doctor.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
 	"text/tabwriter"
 
@@ -63,6 +64,8 @@ func cmdDoctor(args []string) {
 		doctorAppLocation(r, jsonOut)
 	case "modules":
 		doctorModules(r, jsonOut)
+	case "dod":
+		doctorDod(r, jsonOut)
 	default:
 		fmt.Fprintf(os.Stderr, "unknown doctor subcommand: %s\n", sub)
 		doctorUsage()
@@ -90,6 +93,7 @@ Subcommands:
   capabilities    Drift entre docs/capabilities/INDEX.md, tags de funciones, y paginas <grupo>.md (issue 0086)
   app-location    Detecta artefactos (apps/analysis) en carpetas de lenguaje (cpp/apps/, etc.) - issue 0096
   modules         Drift entre uses_modules (app.md) y fn_module_<x> link calls (CMakeLists.txt) - issue 0097
+  dod             Audita bloque dod_evidence_schema en dev/issues/ y dev/flows/ (issue 0114)
 
 Flags:
   --json              Salida JSON (para scripting/agentes)
@@ -588,3 +592,41 @@ func doctorModules(root string, jsonOut bool) {
 		fmt.Println("Fix: align uses_modules in app.md with target_link_libraries(fn_module_*) in CMakeLists.txt.")
 	}
 }
+
+func doctorDod(root string, jsonOut bool) {
+	issuesDir := filepath.Join(root, "dev", "issues")
+	flowsDir := filepath.Join(root, "dev", "flows")
+	report, err := infra.AuditDodSchema(issuesDir, flowsDir)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
+	}
+	if jsonOut {
+		emit(report)
+		return
+	}
+	fmt.Println("=== DoD Schema Audit ===")
+	fmt.Printf("files scanned:  %d\n", report.TotalFiles)
+	fmt.Printf("with schema:    %d\n", report.FilesWithItems)
+	fmt.Printf("total items:    %d\n", report.TotalItems)
+	fmt.Printf("invalid items:  %d\n", report.InvalidItems)
+	if report.InvalidItems == 0 {
+		fmt.Println("\nAll DoD schemas valid.")
+		return
+	}
+	fmt.Println()
+	rel := func(p string) string {
+		if r, err := filepath.Rel(root, p); err == nil {
+			return r
+		}
+		return p
+	}
+	for _, f := range report.Files {
+		if len(f.Errors) == 0 {
+			continue
+		}
+		for _, e := range f.Errors {
+			fmt.Printf("%s : %s\n", rel(f.Path), e)
+		}
+	}
+}