feat: intl site (workbuddy.ai) support + credential hot-reload + build script

- login -intl: sign in via www.workbuddy.ai (browser-based, OneID email/SSO flow)
- per-credential edition routing for refresh/chat upstreams (cn | intl)
- mixed cn/intl account pool with round-robin and 429 cooldown fallback
- English rate-limit message parsing (reset time extraction)
- credential hot-reload: auto discover/add/update/remove credential files while serving (-reload-interval, default 5s, 0=off)
- exclude workbuddy-status.json from credential auto-discovery
- status/monitor/snapshot show per-account site label
- add build.ps1 cross-platform build script; harden .gitignore

.gitignore

@@ -1,19 +1,16 @@
 # 凭据与敏感数据（切勿提交！）
-workbuddy.json
+workbuddy*.json
 workbuddy-console.json
-dist/workbuddy.json
-dist/*.json
 last-*.json
 *.json.bak
 *.json.disabled
+*.disabled
 .workbuddy-*.json
-workbuddy-status.json
 
 # 本地编译产物
+workbuddy-gateway
 workbuddy-gateway.exe
-dist/*.exe
-dist/workbuddy-gateway-linux-*
-dist/workbuddy-gateway-darwin-*
+dist/
 
 # 日志与临时文件
 *.log