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/5e03b6545745463bb8b64813209ffb8c/source/structure.json

@@ -0,0 +1,47 @@
+{
+  "boards": {
+    "7f6ad44692202353": {
+      "uuid": "7f6ad44692202353",
+      "title": "简易数字示波器V1.2",
+      "zIndex": 1
+    }
+  },
+  "schematics": {
+    "de7dd46e6f3a4c1c870fa942ca3bd106": {
+      "uuid": "de7dd46e6f3a4c1c870fa942ca3bd106",
+      "name": "SCH-简易数字示波器V1.2",
+      "board": "7f6ad44692202353",
+      "version": "1704877726000",
+      "updateTime": 1768554350381
+    }
+  },
+  "sheets": {
+    "b0e4b503c24c43188dcceba7ad6b0624": {
+      "uuid": "b0e4b503c24c43188dcceba7ad6b0624",
+      "title": "P1",
+      "schematic_uuid": "de7dd46e6f3a4c1c870fa942ca3bd106",
+      "zIndex": 1,
+      "version": "1709533485000",
+      "updateTime": 1709533485000
+    }
+  },
+  "pcbs": {
+    "d058104df7d94914b370b64676609159": {
+      "uuid": "d058104df7d94914b370b64676609159",
+      "title": "PCB-简易数字示波器V1.2",
+      "board": "7f6ad44692202353",
+      "parent_uuid": "",
+      "version": "1743054665000",
+      "updateTime": 1768554404413
+    }
+  },
+  "panels": {},
+  "blockSymbols": {},
+  "owner": {
+    "uuid": "ebbda44292b4423b92db6e999d50f4d4",
+    "username": "course-examples",
+    "nickname": "EDA课程案例团队",
+    "avatar": "//image.lceda.cn/avatar/jzC6S6odSY18Wlyl8LVUDrnabeedBVOtLS8EyUmL.png",
+    "team": true
+  }
+}