Add GitHub Actions workflow for running tests

- Run tests on push to main and pull requests
- Set up Java 21 and latest Clojure CLI
- Cache dependencies for faster builds
- Run full test suite and reflection checks

Author: handerpeder

.github/workflows/test.yml

@@ -0,0 +1,42 @@
+name: Test
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Setup Java
+      uses: actions/setup-java@v4
+      with:
+        distribution: 'temurin'
+        java-version: '21'
+    
+    - name: Setup Clojure
+      uses: DeLaGuardo/setup-clojure@12.5
+      with:
+        cli: 'latest'
+    
+    - name: Cache dependencies
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/.m2/repository
+          ~/.gitlibs
+          ~/.deps.clj
+        key: ${{ runner.os }}-deps-${{ hashFiles('**/deps.edn') }}
+        restore-keys: |
+          ${{ runner.os }}-deps-
+    
+    - name: Run tests
+      run: clj -M:test
+    
+    - name: Check reflection warnings
+      run: clj -M:test --focus eden.reflection-test