ci: add ESLint workflow

- .gitea/workflows/lint.yml: lint base.js and node/ directory
- .eslintrc.json: browser + node environment, CommonJS
- .gitignore: ignore node_modules/ and .env
- package.json + package-lock.json: eslint@8 dev dependency

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.eslintrc.json

@@ -0,0 +1,11 @@
+{
+    "env": { "browser": true, "node": true, "es2021": true },
+    "parserOptions": { "ecmaVersion": 2021, "sourceType": "script" },
+    "rules": {
+        "no-unused-vars": "warn",
+        "no-undef": "warn",
+        "no-empty": "warn",
+        "semi": ["error", "always"],
+        "eqeqeq": "warn"
+    }
+}

.gitea/workflows/lint.yml

@@ -0,0 +1,20 @@
+name: Lint
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  js-lint:
+    name: JS (eslint)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install ESLint
+        run: npm install --save-dev eslint@8
+
+      - name: Run ESLint
+        run: npx eslint --ext .js base.js node/

.gitignore

@@ -0,0 +1,3 @@
+node_modules/
+.env
+*.env

package.json

@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "eslint": "^8.57.1"
+  }
+}