Function restore_time_index_entry_valid 

pub fn restore_time_index_entry_valid(
    previous: Option<TimeEntry>,
    timestamp: i64,
    relative_offset: u32,
    max_relative: i64,
) -> bool

Validate one decoded time-index entry. Relative offsets strictly advance; timestamps may repeat but may not decrease.

The segment writer emits strictly newer running maxima, at the last offset of the batch that established each maximum. Archive validation also admits repeated maxima: non-decreasing timestamps with advancing offsets suffice for the binary lookup and strict-start kernels. Structural validity cannot establish truthful record prefix bounds; those require faithful construction or a separate semantic check against complete decoded records.