feat(12.2-02): add file removal, caption, reorder and protected downloads

- DELETE, PUT and POST reorder under .../{id}/files/{field}, each scoped by one parent query (404 for a foreign file)
- protected download and thumb routes: is_public=false only, nosniff, private no-store, sandbox CSP, inline only for jpeg/png/gif/webp
- the save applies deferred removals, replaces attachOne files and rechecks maxFiles and required
- blobs of deleted files are removed after commit
- swagger2openapi emits binary content for file responses
- admin OpenAPI, TS types, conformance, README and attachments docs

internal/tools/swagger2openapi/main.go

@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"strings"
 )
 
 func main() {
@@ -322,8 +323,17 @@ func convertResponses(res map[string]any, produces []string) map[string]any {
 			converted[k] = v
 		}
 		if schema != nil {
+			// A Swagger 2.0 file response is binary under the operation's
+			// media types; any other schema (an error envelope next to a
+			// binary success) is JSON.
+			types := produces
+			if m, ok := schema.(map[string]any); ok && m["type"] == "file" {
+				schema = map[string]any{"type": "string", "format": "binary"}
+			} else {
+				types = jsonTypes(produces)
+			}
 			content := map[string]any{}
-			for _, ct := range produces {
+			for _, ct := range types {
 				content[ct] = map[string]any{"schema": schema}
 			}
 			converted["content"] = content
@@ -333,6 +343,21 @@ func convertResponses(res map[string]any, produces []string) map[string]any {
 	return out
 }
 
+// jsonTypes keeps the JSON media types of produces, or application/json
+// when there are none.
+func jsonTypes(produces []string) []string {
+	var out []string
+	for _, ct := range produces {
+		if strings.Contains(ct, "json") {
+			out = append(out, ct)
+		}
+	}
+	if len(out) == 0 {
+		return []string{"application/json"}
+	}
+	return out
+}
+
 func convertSecurity(sec map[string]any) map[string]any {
 	out := make(map[string]any, len(sec))
 	for name, raw := range sec {