fix: Linter errors

Fixed:
- "ineffective break statement. Did you mean to break out of the outer loop?" (SA4011)
- "channels used with os/signal.Notify should be buffered" (SA1017)
- "os.Kill cannot be trapped (did you mean syscall.SIGTERM?)" (SA1016)
- "func envOrDefaultBool is unused" (U1000)
- "should use time.Since instead of time.Now().Sub" (S1012)

ruleset/builtins/geo/geo_loader.go

@@ -49,7 +49,7 @@ func (l *V2GeoLoader) shouldDownload(filename string) bool {
 	if os.IsNotExist(err) {
 		return true
 	}
-	dt := time.Now().Sub(info.ModTime())
+	dt := time.Since(info.ModTime())
 	if l.UpdateInterval == 0 {
 		return dt > geoDefaultUpdateInterval
 	} else {