H-5839, FE-488: Petrinaut: LSP-like interface for Diagnostics and Code Editor

.changeset/bright-ideas-flow.md

@@ -0,0 +1,5 @@
+---
+"@hashintel/petrinaut": minor
+---
+
+Add LSP-based language service layer for Monaco code editors with diagnostics, completions, hover, and signature help

apps/hash-frontend/next.config.js

@@ -219,20 +219,6 @@ export default withSentryConfig(
         // eslint-disable-next-line no-param-reassign
         webpackConfig.resolve.alias.canvas = false;
 
-        if (!isServer) {
-          // Stub Node.js built-ins for browser — needed by `typescript` (used by
-          // @hashintel/petrinaut's in-browser language service)
-          // eslint-disable-next-line no-param-reassign
-          webpackConfig.resolve.fallback = {
-            ...webpackConfig.resolve.fallback,
-            module: false,
-            fs: false,
-            path: false,
-            os: false,
-            perf_hooks: false,
-          };
-        }
-
         webpackConfig.plugins.push(
           new DefinePlugin({
             __SENTRY_DEBUG__: false,

apps/hash-frontend/src/lib/csp.ts

@@ -24,19 +24,13 @@ export const buildCspHeader = (nonce: string): string => {
       "https://apis.google.com",
       // Vercel toolbar / live preview widget
       "https://vercel.live",
-      // @todo FE-488 will make this unnecessary
-      // Monaco Editor loaded from CDN by @monaco-editor/react (used by petrinaut)
-      "https://cdn.jsdelivr.net",
     ],
 
     "style-src": [
       "'self'",
       // Required for Emotion/MUI CSS-in-JS inline style injection.
       // @todo Use nonce-based approach via Emotion's cache `nonce` option.
       "'unsafe-inline'",
-      // @todo FE-488 will make this unnecessary
-      // Monaco Editor stylesheet loaded from CDN by @monaco-editor/react (used by petrinaut)
-      "https://cdn.jsdelivr.net",
     ],
 
     "img-src": [
@@ -51,12 +45,7 @@ export const buildCspHeader = (nonce: string): string => {
       ...(process.env.NODE_ENV === "development" ? ["http:"] : []),
     ],
 
-    "font-src": [
-      "'self'",
-      // @todo FE-488 will make this unnecessary
-      // Monaco Editor CSS embeds the Codicon icon font as an inline base64 data URI
-      "data:",
-    ],
+    "font-src": ["'self'"],
 
     "connect-src": [
       "'self'",

libs/@hashintel/petrinaut/package.json

@@ -55,6 +55,7 @@
     "reactflow": "11.11.4",
     "typescript": "5.9.3",
     "uuid": "13.0.0",
+    "vscode-languageserver-types": "3.17.5",
     "web-worker": "1.4.1"
   },
   "devDependencies": {