Use biome on the frontend for linting, add to CI

.github/workflows/test.yml

@@ -25,8 +25,25 @@ jobs:
       - name: Type check
         run: uv run pyright
 
+  lint-frontend:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: "npm"
+          cache-dependency-path: app/frontend/package-lock.json
+      - name: Install dependencies
+        working-directory: app/frontend
+        run: npm ci
+      - name: Lint and format check
+        working-directory: app/frontend
+        run: npm run check
+
   test:
-    needs: lint
+    needs: [lint, lint-frontend]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4

.pre-commit-config.yaml

@@ -20,3 +20,12 @@ repos:
     rev: v1.1.407
     hooks:
       - id: pyright
+
+  - repo: local
+    hooks:
+      - id: biome
+        name: biome check
+        entry: bash -c 'cd app/frontend && npm run check'
+        language: system
+        files: ^app/frontend/
+        types_or: [javascript, jsx, ts, tsx, json]

app/frontend/biome.json

@@ -1,9 +1,9 @@
 {
 	"$schema": "https://biomejs.dev/schemas/2.2.6/schema.json",
 	"vcs": {
-		"enabled": false,
+		"enabled": true,
 		"clientKind": "git",
-		"useIgnoreFile": false
+		"useIgnoreFile": true
 	},
 	"files": {
 		"ignoreUnknown": false
@@ -15,7 +15,11 @@
 	"linter": {
 		"enabled": true,
 		"rules": {
-			"recommended": true
+			"recommended": true,
+			"a11y": {
+				"noAutofocus": "off",
+				"noSvgWithoutTitle": "off"
+			}
 		}
 	},
 	"javascript": {

app/frontend/components/Chat.tsx

@@ -1,6 +1,5 @@
 "use client";
 
-import { useCallback, useEffect, useState } from "react";
 import {
 	CopilotKit,
 	useCoAgent,
@@ -8,6 +7,7 @@ import {
 	useCopilotAction,
 } from "@copilotkit/react-core";
 import { CopilotChat } from "@copilotkit/react-ui";
+import { useCallback, useEffect, useState } from "react";
 import "@copilotkit/react-ui/styles.css";
 import CitationBlock from "./CitationBlock";
 import DbInfo from "./DbInfo";
@@ -519,7 +519,11 @@ function ChatContentInner({
 							type="button"
 							className={`settings-btn ${initialContext ? "has-context" : ""}`}
 							onClick={() => setSettingsOpen(true)}
-							title={initialContext ? "Background context is set" : "Set background context"}
+							title={
+								initialContext
+									? "Background context is set"
+									: "Set background context"
+							}
 						>
 							<SettingsIcon />
 							Context

app/frontend/components/SettingsPanel.tsx

@@ -133,7 +133,6 @@ export default function SettingsPanel({
 					background: #2563eb;
 				}
 			`}</style>
-			{/* biome-ignore lint/a11y/useKeyWithClickEvents: handled via onKeyDown on overlay */}
 			<div
 				className="settings-modal-overlay"
 				onClick={onClose}