fix(ci): drop container image pull, use setup-java + setup-graalvm

The Quarkus image (docker.io/quarkusio/quarkus-images:tooling-21)
cannot be pulled by the runner (access denied). Replace the
container: block with the standard actions/setup-java (Temurin 21)
and graalvm/setup-graalvm (with native-image component) actions
so the jobs run on the host directly.

.gitea/workflows/ci.yml

@@ -17,18 +17,16 @@ jobs:
   build-jvm:
     name: Build JVM
     runs-on: ubuntu-latest
-    container:
-      image: docker.io/quarkusio/quarkus-images:tooling-21
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Cache Maven
-        uses: actions/cache@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
         with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: ${{ runner.os }}-maven-
+          distribution: temurin
+          java-version: 21
+          cache: maven
 
       - name: Cache Node + npm
         uses: actions/cache@v4
@@ -51,18 +49,23 @@ jobs:
   build-native:
     name: Build Native
     runs-on: ubuntu-latest
-    container:
-      image: docker.io/quarkusio/quarkus-images:tooling-21
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Cache Maven
-        uses: actions/cache@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
         with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: ${{ runner.os }}-maven-
+          distribution: temurin
+          java-version: 21
+          cache: maven
+
+      - name: Set up GraalVM
+        uses: graalvm/setup-graalvm@v1
+        with:
+          distribution: 'graalvm'
+          java-version: '21'
+          components: 'native-image'
 
       - name: Cache Node + npm
         uses: actions/cache@v4