fix: enter coarse edit mode when clock is at preset value

[sheldonsmith-ai]

Summary

• Changes the edit mode entry condition from game_clock_ever_started() to current seconds != default seconds
• When the game clock is at its preset value, edit mode now uses 60-second steps and saves the result as the new default on exit
• The new default is persisted to storage immediately on exit

Test Plan

• Launch app (clock at default, e.g. 25:00) → long-press SELECT → up/down should move in 1-minute increments → press SELECT to exit → kill and relaunch → confirm new value persisted
• Start the clock, pause mid-game → long-press SELECT → up/down should move in 1-second increments → exit should not change the default
• Let clock run to 0 (auto-reset to default) → long-press SELECT → should behave as coarse mode (1-minute steps, saves default)