feat(CI): modular testing and linting system + cursor rule

.github/actions/build-extension/action.yml

@@ -33,14 +33,8 @@ outputs:
 runs:
   using: composite
   steps:
-    - name: Use Node.js 22.x
-      uses: actions/setup-node@v4
-      with:
-        node-version: 22.x
-
-    - name: Install dependencies
-      shell: bash
-      run: npm install --legacy-peer-deps
+    - name: Setup Node and dependencies
+      uses: ./.github/actions/setup-node-deps
 
     - name: Read version
       id: version

.github/actions/run-lint/action.yml

@@ -0,0 +1,11 @@
+name: Run lint
+description: Run ESLint on src.
+
+runs:
+  using: composite
+  steps:
+    - name: Lint
+      shell: bash
+      run: npm run lint
+      env:
+        ESLINT_USE_FLAT_CONFIG: "false"

.github/actions/run-smoke-tests/action.yml

@@ -0,0 +1,9 @@
+name: Run smoke tests
+description: Verify built extension dist output.
+
+runs:
+  using: composite
+  steps:
+    - name: Smoke tests
+      shell: bash
+      run: npm run test:smoke

.github/actions/run-unit-tests/action.yml

@@ -0,0 +1,9 @@
+name: Run unit tests
+description: Run Jest unit tests.
+
+runs:
+  using: composite
+  steps:
+    - name: Unit tests
+      shell: bash
+      run: npm run test:unit

.github/actions/setup-node-deps/action.yml

@@ -0,0 +1,14 @@
+name: Setup Node and dependencies
+description: Install Node.js 22.x and npm dependencies.
+
+runs:
+  using: composite
+  steps:
+    - name: Use Node.js 22.x
+      uses: actions/setup-node@v4
+      with:
+        node-version: 22.x
+
+    - name: Install dependencies
+      shell: bash
+      run: npm install --legacy-peer-deps