fix: healthcheck now tests geo-gate (POST /order) not just GET /markets

Two critical bugs fixed:
1. Old script tested GET /markets (no geo-block) -> UK node passed but
   couldn't actually place orders. Now tests POST /order (geo-blocked):
   401/400 = passed geo-gate, 403 = blocked.
2. Old script only excluded US nodes -> UK/France/Germany/etc could be
   selected. Now uses ALLOWLIST (only JP/HK/KR/TW) instead of blocklist.

Logic unchanged: if current node can place orders -> exit 0 (don't switch).
Only switches when current node fails geo-gate, and only tries JP/HK/KR/TW
nodes.

Moved to host/ in git repo so it syncs with git pull.

host/mihomo-healthcheck.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+# mihomo 代理健康检查 - Polymarket 专用
+# 逻辑：当前节点能下单就不换；不能下单就在日本/香港节点之间切换
+# cron 每 5 分钟跑一次
+
+API="http://127.0.0.1:9090"
+PROXY="http://127.0.0.1:7890"
+
+# 测试当前节点能否通过 Polymarket geo-gate（下单检测，不是读取检测）
+# 用 POST /order 测，403=被block，401=通过（到认证层了）
+test_geo() {
+  code=$(curl -s -o /dev/null -w "%{http_code}" --max-time 10 -x $PROXY \
+    -X POST "https://clob.polymarket.com/order" \
+    -H "Content-Type: application/json" \
+    -d '{}' 2>/dev/null)
+  # 401 = 通过 geo-gate（到认证层了），403 = 被 block
+  if [ "$code" = "401" ] || [ "$code" = "400" ]; then
+    return 0  # 能下单
+  fi
+  return 1  # 不能下单
+}
+
+# 1. 测当前节点能不能下单
+if test_geo; then
+  exit 0  # 能下单，不换
+fi
+
+# 2. 不能下单，在日本和香港节点之间找能用的
+# 只选日本/香港/韩国/台湾（Polymarket 允许的地区）
+nodes=$(curl -s "$API/proxies" | python3 -c "
+import sys, json
+d = json.load(sys.stdin)
+skip = {'DIRECT','REJECT','自动选择','故障转移','良心云','GLOBAL',
+        '剩余流量','套餐到期'}
+# 只允许的地区关键词
+allowed = ['日本', 'JP', 'Japan', '香港', 'HK', 'Hong Kong',
+           '韩国', 'KR', 'Korea', '台湾', 'TW', 'Taiwan']
+for name, info in d.get('proxies', {}).items():
+    if name in skip:
+        continue
+    if info.get('type') in ('Selector','URLTest','Fallback','LoadBalance'):
+        continue
+    # 只选允许地区的节点
+    if not any(k in name for k in allowed):
+        continue
+    print(name)
+")
+
+# 3. 逐个试，找到能下单的就切
+for node in $nodes; do
+  curl -s -X PUT "$API/proxies/GLOBAL" \
+    -H "Content-Type: application/json" \
+    -d "{\"name\":\"$node\"}" > /dev/null
+  sleep 2
+  if test_geo; then
+    logger "mihomo-healthcheck: switched to $node (previous node geo-blocked)"
+    exit 0
+  fi
+done
+
+logger "mihomo-healthcheck: ALL JP/HK nodes failed - check mihomo or subscription"
+exit 1