batch-50: Step 3-4 source download from Guangzhou — 49/50 ok

Run on dev1 (Guangzhou) for the latency advantage. Walltime 3:41 vs
Singapore-estimated 1-2h (~30x speedup, mostly from image.lceda.cn
RTT going from 263ms to 2.6ms).

Pro 25:  24 ok + 1 fail (Super Dial 7f7565ef11 — Pro 2.x legacy
                          schematic/lists 401, separate cookie-perm issue)
         611 docs, 31 MB total
Std 25:  25 ok, 97 docs, 74 MB total
Combined: 49/50 success, 708 docs, 105 MB new disk usage

--max-source-mb 200 cap was not tripped; the 25 Pro candidates are all
under 10 MB, so the 481 MB X86-board outlier from the original sample
was not representative.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

data/raw/oshwhub/d53cd4f3355c45319a36b19cc9ff252e/metadata.json

@@ -55,5 +55,18 @@
     "public": true,
     "publish": true,
     "skipped_files": []
-  }
+  },
+  "source_format": "easyeda-std",
+  "source_path": "source/",
+  "source_documents": [
+    {
+      "doc_uuid": "05e2ed0ec07e462bbcc7ff532846163c",
+      "docType": 1,
+      "master": "4c548c4feacf40c091cec3a2f58a9077",
+      "path": "source/05e2ed0ec07e462bbcc7ff532846163c.json",
+      "size": 169236,
+      "sha256": "c3db3fd27b4d873f3d8b0448546caed505bf8d42ee2fa14d2ee68f0eb56f1321"
+    }
+  ],
+  "editor_version": "6.5.22"
 }