[WIP] Use compressed grid locations in windowed bimatching detailed placer

[AthavanBalakumar]

Updating windowed bipartite matching detailed placer to generate candidate moves using VTR's compressed block grids instead of fixed physical-grid neighbor locations.

The placer now searches compatible locations in compressed-grid space based on each block's logical type. Currently the scope is conservative, skips placement macro members, restricts occupied swaps to blocks of the same logical type, allows moves into empty compatible locations, and keeps floorplan legality checks.

This is a step towards heterogeneous architecture support.

[AthavanBalakumar]

Compared the compressed-grid windowed detailed placer against --ap_detailed_placer none on a hetero test (using k6_frac_N10_frac_chain_mem32K_40nm.xml). Routed wirelength improved on the three tested circuits, min channel width improved on or1200 and sha but worsened on ch_intrinsics.

Circuit	None routed_wirelength	Windowed routed_wirelength	New/old ratio routed_wirelength	None min_chan_width	Windowed min_chan_width	New/old ratio min_chan_width
ch_intrinsics.v	1954	1780	0.910952	32	34	1.062500
or1200.v	41221	39957	0.969336	82	80	0.975610
sha.v	13450	12135	0.902230	82	78	0.951220