close issue 0081: tables promoted to registry + fn doctor cpp-apps BeginTable check

- docs/TQL.md: añadidas secciones joins, views, main_source, 24 viz tokens completos
  (extraidos de tql_helpers.cpp), color_rules, fn.* builtins completos (20 funciones),
  funciones bloqueadas del sandbox, tabla de estado de implementacion actualizada.
  Nota al pie referencia los 129 checks roundtrip (41 emit + 88 apply).

- functions/infra/audit_cpp_apps.go: añadida AuditCppTableMigration() que escanea
  .cpp de cada app imgui buscando ImGui::BeginTable; status CANDIDATE/MIXED/clean
  segun si usa data_table_cpp_viz en uses_functions.

- cmd/fn/doctor.go: fn doctor cpp-apps ahora incluye seccion BeginTable migration
  con tabwriter CANDIDATE/MIXED; --json produce {conformance, table_migration}.
  doctorAll incluye cpp_table_migration en el mapa JSON.

- .claude/rules/fn_doctor.md: tabla de subcomandos y acciones complementarias
  actualizadas con el nuevo check.

- dev/issues/0081 movido a completed/ con status done y notas de deuda documentadas.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/fn/doctor.go

@@ -123,6 +123,11 @@ func doctorAll(root string, jsonOut bool) {
 		} else {
 			all["cpp_apps_error"] = err.Error()
 		}
+		if v, err := infra.AuditCppTableMigration(root); err == nil {
+			all["cpp_table_migration"] = v
+		} else {
+			all["cpp_table_migration_error"] = err.Error()
+		}
 		if v, err := infra.AuditMlEnv(root); err == nil {
 			all["ml"] = v
 		} else {
@@ -168,10 +173,21 @@ func doctorCppApps(root string, jsonOut bool) {
 		fmt.Fprintf(os.Stderr, "error: %v\n", err)
 		os.Exit(1)
 	}
+	tableAudits, err2 := infra.AuditCppTableMigration(root)
+	if err2 != nil {
+		fmt.Fprintf(os.Stderr, "warning: table migration audit failed: %v\n", err2)
+		tableAudits = nil
+	}
+
 	if jsonOut {
-		emit(audits)
+		emit(map[string]any{
+			"conformance":       audits,
+			"table_migration":   tableAudits,
+		})
 		return
 	}
+
+	// Conformance section.
 	bad := 0
 	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
 	fmt.Fprintln(w, "STATUS\tAPP\tISSUES")
@@ -187,6 +203,31 @@ func doctorCppApps(root string, jsonOut bool) {
 	}
 	w.Flush()
 	fmt.Printf("\n%d/%d C++ apps conform.\n", len(audits)-bad, len(audits))
+
+	// BeginTable migration section.
+	if len(tableAudits) == 0 {
+		return
+	}
+	hasMigrationNotes := false
+	for _, t := range tableAudits {
+		if t.Status != "clean" {
+			hasMigrationNotes = true
+			break
+		}
+	}
+	if !hasMigrationNotes {
+		return
+	}
+	fmt.Println("\n--- BeginTable migration (issue 0081) ---")
+	tw := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
+	fmt.Fprintln(tw, "STATUS\tAPP\tTABLES\tMESSAGE")
+	for _, t := range tableAudits {
+		if t.Status == "clean" {
+			continue
+		}
+		fmt.Fprintf(tw, "%s\t%s\t%d\t%s\n", strings.ToUpper(t.Status), t.AppID, t.BeginTableCount, t.Message)
+	}
+	tw.Flush()
 }
 
 func doctorArtefacts(root string, jsonOut bool) {