Add compact JSON formatter with format-on-paste (§03A)

src/app/components/SpecEditor.tsx

@@ -23,6 +23,7 @@ import * as monaco from 'monaco-editor/esm/vs/editor/edcore.main';
 import 'monaco-editor/esm/vs/language/json/monaco.contribution';
 import '../infrastructure/monaco-env'; // side-effect: wire workers before create
 import { configureVegaLiteJson } from '../infrastructure/monaco-schema';
+import { configureJsonFormatter, installFormatOnPaste } from '../infrastructure/monaco-format';
 import { openModal } from '../modals/ModalCoordinator';
 import { useAppStore } from '../stores/AppStore';
 import { confirm } from '../stores/ConfirmStore';
@@ -134,6 +135,8 @@ function EditorSettings() {
 // Register the bundled Vega-Lite schema once: resolves `$schema` locally (no
 // network warning) and powers validation, autocomplete, and hover docs.
 configureVegaLiteJson();
+// Register the compact JSON formatter once (Format Document + format-on-paste, §03A).
+configureJsonFormatter();
 
 function EditorToolbar() {
   const activeId = useSnippetStore((s) => s.activeSnippetId);
@@ -267,6 +270,11 @@ export function SpecEditor() {
       }
     });
 
+    // Pasting reindents the whole spec to keep it consistently formatted (§03A).
+    // The reformat fires onDidChangeModelContent above, so the draft buffer picks
+    // up the formatted text. No-op on the read-only published view / invalid JSON.
+    const pasteSub = installFormatOnPaste(editor);
+
     // Cmd/Ctrl+S is owned globally by the EventRouter (docs/architecture/04 →
     // "bind listeners in exactly one place"), which publishes before the
     // interactive-context gate so it works while the editor has focus. Monaco
@@ -274,6 +282,7 @@ export function SpecEditor() {
 
     return () => {
       sub.dispose();
+      pasteSub.dispose();
       editor.dispose();
       editorRef.current = null;
     };