ci: add dedicated lint job and buildifier config

- Add separate lint job that runs before tests
- Check formatting and warn about common issues early
- Add .buildifier.json config to make lint settings explicit
- Remove duplicate formatting check from test job
- Lint job will fail fast on formatting issues

Author: avrabe

.buildifier.json

@@ -0,0 +1,15 @@
+{
+  "version": 4,
+  "lint": {
+    "mode": "warn",
+    "warnings": [
+      "+load",
+      "+load-on-top",
+      "+out-of-order-load", 
+      "+unused-variable",
+      "+function-docstring",
+      "+function-docstring-args",
+      "+print"
+    ]
+  }
+}

.github/workflows/ci.yml

@@ -10,9 +10,34 @@ env:
   BAZEL_VERSION: 8.3.1
 
 jobs:
+  lint:
+    name: Lint and Format Check
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Install Bazelisk
+      run: |
+        curl -LO https://github.com/bazelbuild/bazelisk/releases/latest/download/bazelisk-linux-amd64
+        chmod +x bazelisk-linux-amd64
+        sudo mv bazelisk-linux-amd64 /usr/local/bin/bazel
+    
+    - name: Check Buildifier Formatting
+      run: |
+        echo "Checking Bazel file formatting..."
+        bazel run //:buildifier -- --lint=warn --mode=check -r .
+    
+    - name: Check for Unused Dependencies
+      run: |
+        echo "Checking for unused dependencies in BUILD files..."
+        # This will warn about unused deps but not fail the build
+        bazel run //:buildifier -- --lint=warn --warnings=load -r . || true
+
   test:
     name: Test on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
+    needs: lint  # Run tests only after lint passes
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
@@ -84,10 +109,6 @@ jobs:
         # Check that WASM files are valid
         bazel build //examples/basic:hello_component
         wasm-tools validate bazel-bin/examples/basic/hello_component.wasm || true
-    
-    - name: Check Formatting
-      run: |
-        bazel run //:buildifier -- --lint=warn --mode=check -r .
 
   integration:
     name: Integration Tests