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.

docs/CACHE_TROUBLESHOOTING.md

@@ -33,7 +33,7 @@ This ensures that cache failures don't cause the entire pipeline to fail.
 
 Updated all existing runner configuration files with:
 - **Auto-detect Host**: Empty host field (allows act_runner to auto-detect the correct IP)
-- **Fixed Port**: `44029` (instead of random port 0)
+- **Fixed Port**: `40047` (instead of random port 0)
 - **Host Network**: Uses host networking for better connectivity
 
 Updated files:
@@ -92,7 +92,7 @@ Update your runner configuration with these key changes:
 cache:
   enabled: true
   host: ""                      # Auto-detect host IP
-  port: 44029                   # Fixed port
+  port: 40047                   # Fixed port
 
 container:
   network: "host"               # Use host networking