Align real FMA ingestion with the user-provided ModelScope source

Constraint: The user supplied a verified archive URL that is a better current source of truth than the previously tested mirror path
Rejected: Keep the older archive URL as the default control surface | Would ignore fresher user evidence and split operational guidance across sources
Confidence: high
Scope-risk: narrow
Directive: Treat the ModelScope FMA archive URL as the primary default until a newer verified source supersedes it
Tested: curl -I -L --max-time 60 https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip; curl -L --range 0-1023 --max-time 60 -o /tmp/fma_modelscope_probe.bin https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip; /usr/local/miniconda3/bin/python acr-engine/scripts/prepare_fma_archive.py inspect
Not-tested: Full archive completion, extraction, and downstream real-data smoke remain pending

@@ -45,7 +45,7 @@ flowchart LR
 
 ### What this script standardizes
 
-- official source URL: `https://os.unil.cloud.switch.ch/fma/fma_small.zip`
+- official source URL: `https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip`
 - resumable archive download to `data/raw/fma_small.zip`
 - extraction target: `data/raw/fma_small_audio/`
 

@@ -8,7 +8,7 @@ import json
 import subprocess
 from pathlib import Path
 
-FMA_SMALL_URL = "https://os.unil.cloud.switch.ch/fma/fma_small.zip"
+FMA_SMALL_URL = "https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip"
 ARCHIVE_PATH = Path("data/raw/fma_small.zip")
 EXTRACT_DIR = Path("data/raw/fma_small_audio")
 

@@ -229,6 +229,34 @@
 
 
 
+
+### Stage: FMA 源切换到 ModelScope
+
+完成项：
+- 将 [acr-engine/scripts/prepare_fma_archive.py](../acr-engine/scripts/prepare_fma_archive.py) 的默认 FMA 整包源切换到用户提供的 ModelScope 地址
+- 同步更新：
+  - [acr-engine/data/raw/README.md](../acr-engine/data/raw/README.md)
+  - [docs/open-dataset-workflow.md](./open-dataset-workflow.md)
+  - [docs/session-handoff.md](./session-handoff.md)
+- 通过 repo 内脚本重新启动托管下载流程
+
+验证结果：
+- `curl -I -L --max-time 60 https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip` 成功
+- 当前响应关键信息：
+  - `200`
+  - `content-length=7679594875`
+  - `accept-ranges: bytes`
+- `curl -L --range 0-1023 ...` 成功获取 `1024` bytes
+- `/usr/local/miniconda3/bin/python scripts/prepare_fma_archive.py inspect` 成功
+- 当前结果：
+  - `archive_url=https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip`
+  - `archive_size=53620736`
+  - 托管下载进程存在：`prepare_fma_archive.py download`
+
+结论：
+- 真实 FMA 下载现在已切换到用户指定的 ModelScope 通道
+- 下载控制面也已统一回 repo 内脚本，后续 session 更容易续传与接力
+
 ### Stage: 服务 HTTP smoke
 
 完成项：
@@ -311,7 +339,7 @@
 - 将该路径补充到开放数据工作流与交接文档
 
 验证结果：
-- `curl -I -L --max-time 60 https://os.unil.cloud.switch.ch/fma/fma_small.zip` 成功
+- `curl -I -L --max-time 60 https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip` 成功
 - 当前响应头关键信息：
   - `200 OK`
   - `Content-Type: application/zip`

@@ -276,7 +276,7 @@
    - [docs/session-handoff.md](./session-handoff.md)
    - [docs/current-capability-map.md](./current-capability-map.md)
    - [acr-engine/FIRST_RUN_CHECKLIST.md](../acr-engine/FIRST_RUN_CHECKLIST.md)
-- FMA 真实子集下载脚手架已存在：[acr-engine/scripts/fetch_fma_subset.py](../acr-engine/scripts/fetch_fma_subset.py)；最近验证结果是旧直链 `403`、页面级历史 URL `404`；但 `https://os.unil.cloud.switch.ch/fma/fma_small.zip` 已验证 `200 OK` 且支持 range
+- FMA 真实子集下载脚手架已存在：[acr-engine/scripts/fetch_fma_subset.py](../acr-engine/scripts/fetch_fma_subset.py)；最近验证结果是旧直链 `403`、页面级历史 URL `404`；但 `https://modelscope.cn/datasets/pengzhendong/fma/resolve/master/fma_small.zip` 已验证 `200 OK` 且支持 range
    - 运行 [acr-engine/scripts/status_snapshot.py](../acr-engine/scripts/status_snapshot.py)
    - 或直接查看最新落盘快照：`acr-engine/.omx/latest_status_snapshot.json`