refactor: update MinerU to use tar.gz and mineru CLI

- Change archive format from zip to tar.gz
- Use 'mineru' CLI command instead of 'magic-pdf'
- Install mineru[all] via pipx in Dockerfile
- Remove zip dependency from Dockerfile
- Update normalizeFiletype to output tar.gz extension
- Update all tests for tar.gz output format
- Simplify README MinerU section

Dockerfile

@@ -139,10 +139,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   pipx \
   # === 系統工具 ===
   locales \
-  zip \
   # === 清理 ===
   && pipx install "markitdown[all]" \
-  && pipx install magic-pdf \
+  && pipx install "mineru[all]" \
   # 清理 apt cache
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/* \