fix(chess): flag flag-fall on a running clock in PlayerClock::time_out()

[abdulwaarith0]

Summary

PlayerClock::time_out() checked the raw remaining_time field, which is only decremented on stop(). While a clock is_running, elapsed time is not yet reflected in remaining_time, so a player who sits on a running clock past zero on their own turn was never reported as flagged — exactly the case flag-detection must catch.

The clock already has get_real_time_remaining(), which subtracts the running elapsed time. This routes time_out() through it:

pub fn time_out(&self) -> bool {
    self.get_real_time_remaining().is_zero()
}

Tests

Added unit tests in time_control.rs:

• stopped clock reports timeout only when remaining_time is zero
• running clock flags when it runs past zero on the mover (raw remaining_time is still non-zero; detection must come from real remaining time)
• running clock with time left is not flagged

All three pass locally.

Closes #941

[abdulwaarith0]

Heads up for reviewers: the failing Test Backend job is a pre-existing breakage on main, unrelated to this PR. The error is E0283: type annotations needed in modules/service/src/games.rs:616 and :678 (the append_query_results mock API under sea-orm 1.1.20) — my diff only touches backend/modules/chess/src/time_control.rs, which compiles cleanly. The last few Backend CI runs on main show the same failure. Happy to fix the games.rs type annotations in a separate PR if that'd be useful.