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/c19a4fc2119f4a44860ccb55ed171e8e/metadata.json

@@ -55,5 +55,34 @@
     "public": true,
     "publish": true,
     "skipped_files": []
-  }
+  },
+  "source_format": "easyeda-std",
+  "source_path": "source/",
+  "source_documents": [
+    {
+      "doc_uuid": "3bbe70ec42bb4bd392096d33fd086096",
+      "docType": 1,
+      "master": "2299d79490ce4ca5a69edc0c7ad16e81",
+      "path": "source/3bbe70ec42bb4bd392096d33fd086096.json",
+      "size": 176103,
+      "sha256": "f985543f654581b001c4d1833ab494daf21ff0bd35986f84ebb8198affd5fd60"
+    },
+    {
+      "doc_uuid": "9a052695bc1a41c7a4ab0d3aa141d866",
+      "docType": 3,
+      "master": "daf11c84c26e4300acf9b30785b540c6",
+      "path": "source/9a052695bc1a41c7a4ab0d3aa141d866.json",
+      "size": 927419,
+      "sha256": "194c44ac52df2356ef60c3d6ad8afea9a6615f1e5b17ba525edadb8cb1ef6668"
+    },
+    {
+      "doc_uuid": "54d66d8b79a94cdd890698e2d40a1323",
+      "docType": 3,
+      "master": "e1716966706743e28d9b435e2fa5ecb6",
+      "path": "source/54d66d8b79a94cdd890698e2d40a1323.json",
+      "size": 931400,
+      "sha256": "1f79b244cea82518a741cf6abfb46de0a452b320945ef79d928b648678a9d109"
+    }
+  ],
+  "editor_version": "6.5.37"
 }