chore: memory-sync — 新增 obsidian 插件记录 + memcore 路径锁定决策归档

- decisions.md 新增 memcore memory-update/lint 路径锁定决策条目
- project_overview.md 已发布插件表新增 obsidian 插件族（9 个技能）
- CLAUDE.md 已发布插件表同步更新，顶部元数据刷新至 9c91382
- MEMORY.md / lint_report.md 索引与执行时间更新至 2026-05-08

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -1,4 +1,4 @@
-<!-- Last updated: 2026-05-01 | Commit: 0c46ed0 -->
+<!-- Last updated: 2026-05-08 | Commit: 9c91382 -->
 # CLAUDE.md
 
 This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
@@ -78,6 +78,7 @@ description: 一句话说明该技能的用途（Claude 用此判断何时触发
 |------|------|------|
 | `huanxi` | `/huanxi-shared` `/huanxi-report` `/huanxi-leader` `/huanxi-task` `/huanxi-weekly` `/huanxi-org` | 寰汐企业管理系统完整工作流，含 MCP Server 自动配置 |
 | `memcore` | `/memory-sync` `/memory-update` `/memory-lint` | 项目记忆体系核心引擎 |
+| `obsidian` | `/obsidian` `/obsidian-bases` `/obsidian-daily` `/obsidian-history` `/obsidian-meta` `/obsidian-plugins` `/obsidian-search` `/obsidian-tasks` `/obsidian-workflow-pkm` | Obsidian 知识库完整工作流（9 个技能） |
 
 ### memcore 技能调用关系