bug: Lobby countdown displays wrong time — ticks vs seconds mismatch

Description

The lobby HUD displays "02:00" (120 seconds) when only 6 real seconds pass. The root cause is a ticks-vs-seconds unit mismatch: the phase duration is stored in ticks (e.g. 120 ticks = 6 seconds at 20 TPS) but the HUD formats it as if it were seconds.

Acceptance Criteria

• The countdown displays the correct wall-clock time remaining (e.g. "0:06" for 120 ticks at 20 TPS)
• The conversion `ticks / 20 = seconds` is applied before formatting
• A shared utility method `TickUtils.toSeconds(long ticks)` is introduced to prevent future mismatches
• Unit test covers the conversion and the display formatting

Technical Details

• Bug is in the `GameHud` countdown formatter or the value passed to it from `LobbyPhase`
• Check all phase duration constants for unit consistency (ticks vs seconds vs milliseconds)
• `TimedPhase` (if used) stores duration — verify its unit contract

Dependencies

None

Estimate

S

Trace the countdown from LobbyPhase through GameHud, and inspect TimedPhase if it is used, checking the unit contract for each phase duration. Introduce the requested TickUtils.toSeconds(long ticks) utility and cover both conversion and display formatting with unit tests. Done means 120 ticks displays as 0:06 at 20 TPS and related duration constants use consistent units.