Initial commit: frpc-client-win v1.0

Single-file Windows frpc service wrapper.

Features:
- Embeds frpc v0.70.1 (16.7MB) into one 18.9MB EXE
- Registers as Windows Service (auto-start, no login required)
- Auto-detects frpc config by three-tier search:
  1. frpc.ini  2. frpc.toml  3. any *.ini/*.toml in exe dir
- Self-healing supervisor: frpc crashes are restarted with
  exponential backoff (2s..60s), capped to avoid log spam
- Console subsystem so install/start show feedback
- FreeConsole on SCM start to suppress console window
- Logs to <exe-dir>/logs/service.log

Subcommands:
  install  start  stop  remove  import  -d

Smoke test (smoke_linux.go) covers all config detection paths
including the custom-name (e.g. frpc-mike.ini) use case.

internal/service/signals_unix.go

@@ -0,0 +1,15 @@
+//go:build !windows
+// +build !windows
+
+package service
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+// signalNotify 跨平台注册 Ctrl+C / SIGTERM。
+func signalNotify(ch chan<- os.Signal) {
+	signal.Notify(ch, os.Interrupt, syscall.SIGTERM)
+}