refactor(core): add headless run and auto-restart

- Run without console by default
- Log to file once console hidden
- Recover panics in background goroutines
- Restart agent after unexpected errors
- Use shared instance launch helper

lib/crashlog/crashlog.go

@@ -13,11 +13,10 @@ import (
 
 var mu sync.Mutex
 
-// Recover logs a panic and re-raises after writing the crash file.
+// Recover logs a panic without re-raising (used by optional defer wrappers).
 func Recover() {
 	if r := recover(); r != nil {
 		_ = write("panic", fmt.Sprint(r), debug.Stack())
-		panic(r)
 	}
 }