Keep the song-centric manifest import docs mechanically clean

Constraint: Preserve the just-validated manifest import workflow while removing formatting noise from the retained docs set.
Rejected: Leave doc formatting drift after a live-validated workflow change | It accumulates avoidable friction for later edits and checks.
Confidence: high
Scope-risk: narrow
Directive: Run diff-check and docs link validation after each docs-only follow-up on the reduced docs surface.
Tested: git diff --check; /usr/local/miniconda3/bin/python scripts/check_markdown_links.py --root docs returned OK for 11 active markdown files
Not-tested: no runtime logic changes in this cleanup commit

 # PostgreSQL DB Schema Samples / 融合优先 DDL 草案与查询样例
 
-> 更新：2026-06-04  
+> 更新：2026-06-04
 > 目标：把当前 **song-centric + 融合优先** 设计落成一版可以直接评审和继续实现的 PostgreSQL DDL 草案。
 > SQL 文件：[`acr-engine/sql/acr_pg_schema_songcentric_v1.sql`](../acr-engine/sql/acr_pg_schema_songcentric_v1.sql)
 > live smoke：[`acr-engine/scripts/smoke_songcentric_schema_live.py`](../acr-engine/scripts/smoke_songcentric_schema_live.py)
@@ -264,7 +264,7 @@ flowchart TD
     B --> F[set_membership]
 ```
 
-当前样例 manifest：[`acr-engine/data/pgvector_eval/music20/songcentric_manifest_sample.jsonl`](../acr-engine/data/pgvector_eval/music20/songcentric_manifest_sample.jsonl)  
+当前样例 manifest：[`acr-engine/data/pgvector_eval/music20/songcentric_manifest_sample.jsonl`](../acr-engine/data/pgvector_eval/music20/songcentric_manifest_sample.jsonl)
 当前导入脚本：[`acr-engine/scripts/import_songcentric_manifest_live.py`](../acr-engine/scripts/import_songcentric_manifest_live.py)
 
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