feat: add native/Java auth SDK, docs, CI, and examples

Made-with: Cursor

.github/workflows/ci-java.yml

@@ -0,0 +1,28 @@
+name: ci-java
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+jobs:
+  maven:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "17"
+          cache: maven
+      - name: Build native (.so)
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y build-essential cmake
+          cmake -S native -B native/build -DCMAKE_BUILD_TYPE=Release
+          cmake --build native/build --parallel
+      - name: Maven verify
+        run: mvn -f java/pom.xml -B verify
+        env:
+          LD_LIBRARY_PATH: ${{ github.workspace }}/native/build