fix: remove cache mount from Dockerfile for Railway compatibility

Railway has specific cache mount ID requirements. Removing the cache mount
since Railway has its own caching system and uv is fast enough without it.

Author: carlosmgv02

Dockerfile

@@ -10,8 +10,7 @@ COPY pyproject.toml uv.lock README.md ./
 COPY src ./src
 
 # Install dependencies (no dev dependencies in production)
-RUN --mount=type=cache,id=uv-cache,target=/root/.cache/uv \
-    uv sync --frozen --no-dev --extra mcp
+RUN uv sync --frozen --no-dev --extra mcp
 
 # Expose port (Railway will set PORT env var)
 EXPOSE 8080