feat(dashboard): CodeEditor readOnly prop

Threads readOnly through to EditorState.readOnly + EditorView.editable so
script-detail can render a viewer-only editor without intercepting
keystrokes upstream.

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

dashboard/src/lib/CodeEditor.svelte

@@ -25,12 +25,18 @@
 		value = $bindable(''),
 		language = 'rhai' as Language,
 		placeholder = '',
-		minHeight = '12rem'
+		minHeight = '12rem',
+		readOnly = false
 	}: {
 		value?: string;
 		language?: Language;
 		placeholder?: string;
 		minHeight?: string;
+		/** When true the editor renders without a cursor and rejects
+		 *  keystrokes. Parent-driven `value` changes still apply via
+		 *  the dispatch path below — this only blocks user edits.
+		 *  Not reactive after mount; re-mount via `{#key}` if needed. */
+		readOnly?: boolean;
 	} = $props();
 
 	let host: HTMLDivElement | null = null;
@@ -48,6 +54,12 @@
 			keymap.of([indentWithTab]),
 			dashboardSyntaxHighlighting,
 			dashboardTheme,
+			// readOnly + editable together: readOnly blocks the
+			// underlying transactions, editable suppresses the caret
+			// + selection visuals so the user can see it's not
+			// editable.
+			EditorState.readOnly.of(readOnly),
+			EditorView.editable.of(!readOnly),
 			EditorView.updateListener.of((update) => {
 				if (update.docChanged && !pushingFromOutside) {
 					value = update.state.doc.toString();