docs: 清理过期计划文档并补全 work-log 与开发/用户文档

- 删除已落地的 improvement-roadmap、superpowers 计划与 ui-mockups 参考稿，删除早期 work-log（2026-05-06~08）
- 新增 2026-05-23 起的 work-log 与 attachment-association-background-job、reimbursement-draft-action-branching 等开发文档及用户文档
- docker-compose(.full).yml 微调服务配置

docker-compose.yml

@@ -29,7 +29,7 @@ services:
       - >
         apt-get update &&
         DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends
-        python3 python3-pip python3-venv fontconfig openssh-server poppler-data &&
+        python3 python3-pip python3-venv fontconfig openssh-server poppler-data mupdf-tools &&
         if ! fc-match 'Noto Sans CJK SC' | grep -qi 'Noto'; then if ! timeout "${CJK_FONT_INSTALL_TIMEOUT_SECONDS:-45}" sh -lc 'DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends fonts-noto-cjk fonts-noto-cjk-extra'; then printf '%s\n' '[WARN] CJK font installation timed out or failed; continuing startup without blocking the app.'; fi; fi &&
         printf '%s\n'
         '<?xml version="1.0"?>'