feat: evaluate comments and audit-log tools for review workflows

[pandaria75]

背景

后续如果把 BookStack 作为写作实验仓库，人工审阅意见和修改记录可能很有价值。

BookStack comments 和 audit-log 能力可能可用于审稿记录、人工修改追踪和实验分析。

目标

评估是否需要新增：

• list_comments
• create_comment
• update_comment
• delete_comment
• list_audit_log

非目标

当前不直接实现，先做能力评估和设计建议。

验收标准

• 说明 comments 是否适合承载审稿意见。
• 说明 audit-log 是否适合追踪人工修改。
• 给出 P1/P2/P3 优先级建议。

[pandaria75]

Completed evaluation for #46 in task planning artifacts.

Summary:

• BookStack comments are a reasonable future fit for review-feedback workflows.
• Audit-log access is more useful for human/admin investigation than for routine LLM tool invocation.
• Risks include exposing sensitive review text, user identities, and broader operational history.

Recommendation:

• Comments: P1 future candidate, likely starting with read-oriented workflows.
• Audit log: P3 and likely admin-only unless a later requirement justifies a constrained read-only view.

No production implementation for #46 is included in this task.