fix: Resolve mvn command not found error in CI workflow

- Replace 'mvn' commands with './mvnw' in CI workflow
- Add chmod +x ./mvnw step to make Maven wrapper executable
- Add cache: maven to Java setup step for better caching
- Update troubleshooting scripts to use correct port 40047
- Update documentation to reflect port change

This fixes the 'mvn: command not found' error by ensuring
all Maven commands use the Maven wrapper (mvnw) which is
included in the project and doesn't require Maven to be
pre-installed on the runner.

.gitea/workflows/ci.yml

@@ -27,6 +27,10 @@ jobs:
       with:
         java-version: '17'
         distribution: 'temurin'
+        cache: maven
+        
+    - name: Make Maven wrapper executable
+      run: chmod +x ./mvnw
         
     - name: Cache Maven dependencies
       uses: actions/cache@v4
@@ -37,13 +41,13 @@ jobs:
         fail-on-cache-miss: false
         
     - name: Run tests
-      run: mvn test
+      run: ./mvnw test
       
     - name: Run code quality checks
-      run: mvn spotbugs:check checkstyle:check
+      run: ./mvnw spotbugs:check checkstyle:check
       
     - name: Build application
-      run: mvn clean package -DskipTests
+      run: ./mvnw clean package -DskipTests
       
     - name: Build Docker image (test only)
       run: docker build -t api-gateway:test .