feat(adc): UN 标定完成、标定脚本归集到 test/host/cal/

- UN 通道 5 点最小二乘标定完成：r=555.382141, b=-1, 残差 0.038%, R²=0.99999967
- UA/IA/UN 三路 VALID 置位，保护解卡
- ROM 默认值更新为当前标定值（ADC_CAL_R_Q16_VOLT=555.144958）
- UB/UC/UN 通过 104 写入 ROM 默认值，config.ini 同步
- cal_fit.py 新增 ROLD 表自动读取，不再需要手传 --r-old
- 执行卡精简至 126 行，新增 cal_collect.py 采集脚本与 ROLD 填表
- 标定脚本（cal_fit/cal_write/cal_collect）归集到 test/host/cal/
- 全库文档路径引用同步更新（8 文件）
- UN 当前态文档改写：明确零序电压 U0 语义、本台架未接线状态
- 删除已失效的外部知识底座文档链接

scripts/size_attestation.json

@@ -1,15 +1,15 @@
 {
-  "built_at": "2026-11-13T08:03:21+08:00",
-  "fingerprint": "09cfe12df7414b5c2a91aedf39623942a8be2f36c188e2186f54c245b47e30f2",
+  "built_at": "2026-11-13T11:25:00+08:00",
+  "fingerprint": "39f4f69a673f97c33cc59b301e723ec8f1e03686f4556ac6abb1a5a6cd438796",
   "fingerprint_files": 1479,
   "fingerprint_source": "git-index",
   "gated_regions": [
     "RW_IRAM1",
     "RW_CCM"
   ],
-  "git_head": "1355dbe1b13e9bf43f2a0be0ff290a8a9dd208cd",
+  "git_head": "7c505b2457d977adf7750abbb841b0453fd6bfb9",
   "map": "MDK-ARM/STM32F407-Demo/STM32F407-Demo.map",
-  "map_mtime": 1794528195,
+  "map_mtime": 1794540294,
   "pct": {
     "ER_IROM1": 27.46,
     "RW_CCM": 87.89,
@@ -19,7 +19,7 @@
   "regions": {
     "ER_IROM1": {
       "max": 1048576,
-      "size": 287960
+      "size": 287964
     },
     "RW_CCM": {
       "max": 65280,
@@ -37,7 +37,7 @@
   "schema": 2,
   "scope_note": "\u540c\u7801\u51ed\u8bc1\uff1a\u6307\u7eb9\u8986\u76d6\u56fa\u4ef6\u4f53\u79ef\u76f8\u5173\u6e90\u7801\uff0c\u53e3\u5f84\u89c1\u672c\u811a\u672c docstring",
   "sizes": {
-    "code": 256196,
+    "code": 256200,
     "ro_data": 31764,
     "rw_data": 2080,
     "zi_data": 152368