- Win detection now uses per-player row/col/diagonal counters instead of
scanning lines; O(1) per move and works for any board size (change N)
- Moved spielfeld into gameState as board[N][N]; removed global
- Replaced recursive getUserInput with a loop to avoid stack overflow
on repeated bad input; also handles non-integer cin failures
- Initialized gameState::winner to ' ' to avoid undefined behaviour
- Fixed draw output: prints "Unentschieden!" instead of "Der Gewinner ist: -"
- Removed stale TODO comment that incorrectly claimed draw detection was broken
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
