Force rebuild with cache bust and Docker improvements

- Add pip upgrade to Dockerfile
- Add app_port configuration to README
- Add license field
- Create .cachebust file to force rebuild
- Use --no-cache-dir flag properly

.cachebust

@@ -0,0 +1,2 @@
+CACHE_BUST=2025-07-10-16:52:00
+VERSION=0.3.0

Dockerfile

@@ -16,6 +16,7 @@ WORKDIR /app
 
 # Copy and install requirements
 COPY --chown=user requirements.txt .
+RUN pip install --no-cache-dir --upgrade pip
 RUN pip install --no-cache-dir -r requirements.txt
 
 # Copy application code

README.md

@@ -5,6 +5,8 @@ colorFrom: blue
 colorTo: indigo
 sdk: docker
 pinned: false
+license: mit
+app_port: 7860
 ---
 
 # MinerU PDF to Markdown Converter