refactor(vault): Phase 3 — metadata convergence

- Backfill `created` frontmatter on 266 active notes (git date or mtime)
- Normalize `status` to 4 values: draft/active/done/archived (11 notes)
  - Active/进行中/needs-review → active
  - archive → archived
  - 待执行/conditional → draft
  - 完成/accepted → done
- Declare clipper boundary: 04_Archive/Inbox-Clippings/** exempt from migration
- Update depth rule: max 3 → max 4 levels (new notes only)
- Add metadata-converge.mjs script for reproducibility

02_Areas/House/CLAUDE.md

@@ -1,3 +1,6 @@
+---
+created: 2026-01-26
+---
 <claude-mem-context>
 # Recent Activity
 

02_Areas/House/low-volume-mono-laser-mfp-buying-guide-2026-08.md

@@ -1,3 +1,6 @@
+---
+created: 2026-08-17
+---
 # 低打印量黑白激光一体机：采购决策树（2026-08）
 
 ## 结论

02_Areas/House/sirivision-sr-s25g3218f-research-2026-08.md

@@ -1,3 +1,6 @@
+---
+created: 2026-08-17
+---
 # 希力威视 SR-S25G3218F 调查（2026-08-08）
 
 **结论：** 若需求是大量 2.5G 终端、少量 10G 光上联，`SR-S25G3218F` 的端口密度