feat(devops): add Oxlint alongside ESLint for incremental migration

.github/workflows/ci.yml

@@ -46,8 +46,8 @@ jobs:
       - run: npm ci
       - run: npm run test:coverage
 
-  eslint:
-    name: 🔍 ESLint
+  lint:
+    name: 🔍 Lint
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
@@ -57,7 +57,7 @@ jobs:
           node-version: "24"
           cache: "npm"
       - run: npm ci
-      - run: npx eslint --format gha
+      - run: npm run lint:github
 
   prettier:
     name: 🎨 Prettier

.husky/pre-commit

@@ -6,4 +6,4 @@
 export PATH="/usr/local/bin:$HOME/.npm-global/bin:$HOME/.nvm/versions/node/$(node -v)/bin:$PATH"
 
 # Then run lint-staged if tests pass
-npx lint-staged
+npx lint-staged --concurrent false

.oxlintrc.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "env": {
+    "browser": true,
+    "node": true
+  },
+  "ignorePatterns": [
+    "src/server/gatekeeper/**",
+    "tests/pathfinding/playground/**"
+  ],
+  "categories": {
+    "correctness": "off",
+    "suspicious": "off",
+    "pedantic": "off",
+    "perf": "off",
+    "style": "off",
+    "restriction": "off",
+    "nursery": "off"
+  },
+  "options": {
+    "typeAware": true
+  },
+  "rules": {
+    "typescript/no-explicit-any": "off",
+    "typescript/prefer-nullish-coalescing": "error",
+    "eqeqeq": "error",
+    "no-case-declarations": "error",
+    "no-unused-vars": "off"
+  }
+}

CLAUDE.md

@@ -11,8 +11,8 @@ npm run start:client     # Client only
 npm run start:server-dev # Server only
 npm test                 # Run all tests (Vitest)
 npm run test:coverage    # Tests with coverage
-npm run lint             # ESLint
-npm run lint:fix         # ESLint with auto-fix
+npm run lint             # Oxlint + ESLint
+npm run lint:fix         # Oxlint + ESLint with auto-fix
 npm run format           # Prettier
 npm run build-prod       # Production build
 ```

CONTRIBUTING.md

@@ -68,7 +68,7 @@ git checkout -b fix/issue-number-bug-name
 
 ### Coding Standards
 
-We enforce code quality using ESLint and Prettier.
+We enforce code quality using Oxlint, ESLint, and Prettier. ESLint remains during the Oxlint migration as a compatibility backstop.
 
 - **Format Code**:
   ```bash

README.md

@@ -121,13 +121,13 @@ npm run dev:prod
   npm run format
   ```
 
-- **Lint code**:
+- **Lint code with Oxlint and ESLint**:
 
   ```bash
   npm run lint
   ```
 
-- **Lint and fix code**:
+- **Lint and fix code with Oxlint and ESLint**:
 
   ```bash
   npm run lint:fix