Fix Monaco editor syntax highlighting in Preview block (#2459)

The Preview block's CodeEditPreview component was not passing file
information to Monaco editor, preventing automatic language detection
from file extensions.

Changes:
- Add fileName prop to CodeEditor component
- Pass actual file path to Monaco with fallback to random UUID

Fixes syntax highlighting for all text files opened in Preview blocks
while maintaining backward compatibility with existing CodeEditor usage.

---------

Co-authored-by: sawka

Author: slate20

frontend/app/onboarding/onboarding-command.tsx

@@ -1,7 +1,7 @@
 // Copyright 2025, Command Line Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-import { useCallback, useLayoutEffect, useState } from "react";
+import { useCallback, useLayoutEffect, useRef, useState } from "react";
 import { FakeBlock } from "./onboarding-layout";
 import waveLogo from "/logos/wave-logo.png";
 
@@ -114,6 +114,7 @@ export const ViewLogoCommand = ({ onComplete }: { onComplete?: () => void }) =>
 };
 
 export const EditBashrcCommand = ({ onComplete }: { onComplete?: () => void }) => {
+    const fileNameRef = useRef(`${crypto.randomUUID()}/.bashrc`);
     const bashrcContent = `# Aliases
 alias ll="ls -lah"
 alias gst="git status"
@@ -127,7 +128,13 @@ export PATH="$HOME/.local/bin:$PATH"`;
 
     return (
         <FakeCommand command="wsh edit ~/.bashrc" onComplete={onComplete}>
-            <FakeBlock icon="file-lines" name=".bashrc" editorText={bashrcContent} />
+            <FakeBlock
+                icon="file-lines"
+                name=".bashrc"
+                editorText={bashrcContent}
+                editorFileName={fileNameRef.current}
+                editorLanguage="shell"
+            />
         </FakeCommand>
     );
 };

frontend/app/onboarding/onboarding-layout.tsx

@@ -15,9 +15,21 @@ export type FakeBlockProps = {
     markdown?: string;
     imgsrc?: string;
     editorText?: string;
+    editorFileName?: string;
+    editorLanguage?: string;
 };
 
-export const FakeBlock = ({ icon, name, highlighted, className, markdown, imgsrc, editorText }: FakeBlockProps) => {
+export const FakeBlock = ({
+    icon,
+    name,
+    highlighted,
+    className,
+    markdown,
+    imgsrc,
+    editorText,
+    editorFileName,
+    editorLanguage,
+}: FakeBlockProps) => {
     return (
         <div
             className={cn(
@@ -37,7 +49,13 @@ export const FakeBlock = ({ icon, name, highlighted, className, markdown, imgsrc
             <div className="flex-1 flex items-center justify-center overflow-auto p-4">
                 {editorText ? (
                     <div className="w-full h-full">
-                        <CodeEditor blockId="fake-block" text={editorText} readonly={true} language="shell" />
+                        <CodeEditor
+                            blockId="fake-block"
+                            text={editorText}
+                            readonly={true}
+                            fileName={editorFileName}
+                            language={editorLanguage ?? "shell"}
+                        />
                     </div>
                 ) : imgsrc ? (
                     <img src={imgsrc} alt={name} className="max-w-full max-h-full object-contain" />

frontend/app/view/codeeditor/codeeditor.tsx

@@ -108,19 +108,27 @@ interface CodeEditorProps {
     text: string;
     readonly: boolean;
     language?: string;
+    fileName?: string;
     onChange?: (text: string) => void;
     onMount?: (monacoPtr: MonacoTypes.editor.IStandaloneCodeEditor, monaco: Monaco) => () => void;
 }
 
-export function CodeEditor({ blockId, text, language, readonly, onChange, onMount }: CodeEditorProps) {
+export function CodeEditor({ blockId, text, language, fileName, readonly, onChange, onMount }: CodeEditorProps) {
     const divRef = useRef<HTMLDivElement>(null);
     const unmountRef = useRef<() => void>(null);
     const minimapEnabled = useOverrideConfigAtom(blockId, "editor:minimapenabled") ?? false;
     const stickyScrollEnabled = useOverrideConfigAtom(blockId, "editor:stickyscrollenabled") ?? false;
     const wordWrap = useOverrideConfigAtom(blockId, "editor:wordwrap") ?? false;
     const fontSize = boundNumber(useOverrideConfigAtom(blockId, "editor:fontsize"), 6, 64);
     const theme = "wave-theme-dark";
-    const editorPath = useRef(crypto.randomUUID()).current;
+    const uuidRef = useRef(crypto.randomUUID()).current;
+    let editorPath: string;
+    if (fileName) {
+        const separator = fileName.startsWith("/") ? "" : "/";
+        editorPath = blockId + separator + fileName;
+    } else {
+        editorPath = uuidRef;
+    }
 
     React.useEffect(() => {
         return () => {

frontend/app/view/preview/preview-edit.tsx

@@ -12,10 +12,35 @@ import type * as MonacoTypes from "monaco-editor/esm/vs/editor/editor.api";
 import { useEffect } from "react";
 import type { SpecializedViewProps } from "./preview";
 
+export const shellFileMap: Record<string, string> = {
+    ".bashrc": "shell",
+    ".bash_profile": "shell",
+    ".bash_login": "shell",
+    ".bash_logout": "shell",
+    ".profile": "shell",
+    ".zshrc": "shell",
+    ".zprofile": "shell",
+    ".zlogin": "shell",
+    ".zlogout": "shell",
+    ".kshrc": "shell",
+    ".cshrc": "shell",
+    ".tcshrc": "shell",
+    ".xonshrc": "python",
+    ".shrc": "shell",
+    ".aliases": "shell",
+    ".functions": "shell",
+    ".exports": "shell",
+    ".direnvrc": "shell",
+};
+
 function CodeEditPreview({ model }: SpecializedViewProps) {
     const fileContent = useAtomValue(model.fileContent);
     const setNewFileContent = useSetAtom(model.newFileContent);
     const fileInfo = useAtomValue(model.statFile);
+    const fileName = fileInfo?.path || fileInfo?.name;
+
+    const baseName = fileName ? fileName.split("/").pop() : null;
+    const language = baseName && shellFileMap[baseName] ? shellFileMap[baseName] : undefined;
 
     function codeEditKeyDownHandler(e: WaveKeyboardEvent): boolean {
         if (checkKeyPressed(e, "Cmd:e")) {
@@ -65,6 +90,8 @@ function CodeEditPreview({ model }: SpecializedViewProps) {
         <CodeEditor
             blockId={model.blockId}
             text={fileContent}
+            fileName={fileName}
+            language={language}
             readonly={fileInfo.readonly}
             onChange={(text) => setNewFileContent(text)}
             onMount={onMount}