ci: add verbose logging and cache cleanup for debugging

Add comprehensive debug output to CI build step to diagnose
build failures:
- Log Node.js and npm versions
- Check node_modules state
- Clean cache directories before build
- Capture full build output to build.log

This will help identify the root cause of CI build failures.

.woodpecker.yml

@@ -123,9 +123,18 @@ steps:
       - lint
       - type-check
     commands:
+      - echo "=== Debug: Environment info ==="
+      - node --version
+      - npm --version
+      - echo "=== Debug: Checking node_modules ==="
+      - ls -la node_modules/ | head -20
+      - echo "=== Debug: Cleaning cache ==="
+      - rm -rf node_modules/.cache
+      - rm -rf .next
+      - rm -rf dist
       - echo "Building production artifacts"
-      - npm run build
-      - echo "Build completed"
+      - npm run build 2>&1 | tee build.log
+      - echo "=== Debug: Build completed ==="
       - ls -la dist/
       - echo "Deploying to production"
       - mkdir -p ~/.ssh