Initial version with basic grid generation functionality.
Performance optimizations based on multi-resolution benchmarks (50m-1000m cell sizes):
Refined adaptive worker scaling: <50k cells use max 4 workers, <500k cells use max 8 workers, <2M cells use max 16 workers. This minimizes parallelization overhead which can reduce performance by up to 50% on small grids.
Benchmarks show 8 workers provide optimal performance for most grid sizes (50m-500m cells).
Default tile_multiplier set to 1, as benchmarks show tile_mult=2 consistently reduces performance (e.g., 50m cells: 1.97x speedup with mult=1 vs 1.47x with mult=2).
Added user-facing warnings when >32 workers are configured (performance typically decreases due to overhead) or when tile_multiplier > 1 is set.
