Документация и runtime: полный production-fix по fix6 без legacy

reboot_module/src/main.rs

@@ -96,6 +96,9 @@ fn persist_plan(planned: NaiveDateTime) {
 fn next_reboot_time(start_hhmm: &str, end_hhmm: &str) -> anyhow::Result<NaiveDateTime> {
     let start = parse_hhmm(start_hhmm)?;
     let end = parse_hhmm(end_hhmm)?;
+    if start == end {
+        anyhow::bail!("reboot window start and end must differ");
+    }
 
     let now = Utc::now().naive_utc();
     let now_t = NaiveTime::from_hms_opt(now.hour(), now.minute(), now.second())
@@ -233,5 +236,11 @@ mod tests {
         assert_eq!(s, now);
         assert_eq!(e.format("%Y-%m-%d %H:%M:%S").to_string(), "2026-01-11 02:00:00");
     }
+
+    #[test]
+    fn equal_window_boundaries_rejected() {
+        let err = next_reboot_time("01:00", "01:00").err();
+        assert!(err.is_some());
+    }
 }