ADR-0001 Rev 2: 51-bit PhysAddr layout with concrete sub-unit tables

Remove rack_id (4 bits), rename sip_seg→die_id, shift fields to enable
42-bit local_offset (4 TB per die). Define PE_LOCAL/MCPU_LOCAL/CUBE_SRAM
sub-unit tables for AHBM dies and IOCPU sub-unit table for IOCHIPLET
dies (1 TB window). Supersedes ADR-0031.

Also fixes latent VA/PA confusion in pe_dma pipeline DMA path where
virtual addresses were decoded as physical addresses without MMU
translation — previously masked by coincidental bit-position alignment.

529 passed (+6 recovered), 10 pre-existing failures unchanged.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_va_offset.py

@@ -70,7 +70,7 @@ def _make_standalone(shape, num_pe=NUM_PE):
         sram_bytes_per_cube=32 * _MB,
     )
     allocators = {
-        (0, 0, i): PEMemAllocator(rack_id=0, sip_id=0, cube_id=0, pe_id=i, cfg=cfg)
+        (0, 0, i): PEMemAllocator(sip_id=0, die_id=0, pe_id=i, cfg=cfg)
         for i in range(num_pe)
     }
     va_alloc = VirtualAllocator(va_base=0x1_0000_0000, va_size=64 * _GB, page_size=4096)