D463 - The guest mapping arena is moved clear of the thunk data blocks

measured - 2026-09-01 (user-directed /loop: overnight oracle-free crunch)

MAPPING_BASE - where a guest map goes when it expresses no address preference - was 0x0000_7200_0000_0000, which is orbistoun_thunk::SUGGESTED_DATA_BASE exactly. The thunk data blocks are reserved at that address when the guest is loaded, so the first guest map with no hint (next_mapping_base starts the counter at MAPPING_BASE) landed on top of them: VirtualAlloc refused the address, reserve returned a conflict, and map answered NoMemory - which the guest read as out-of-memory and faulted through the null it kept. PPSA04263 died this way at image+0x2ba64c1 after 32 calls, and the collision was invisible until D462's diagnostic named the base.

A title that reserves with a hint first - PPSA02664 calls sceKernelReserveVirtualRange at its own 0x5000… address - never reached MAPPING_BASE, which is why the same allocator wall looked title-specific rather than structural. It is not: any guest that maps without a hint hits it.

MAPPING_BASE moved to 0x0000_7400_0000_0000, a clear terabyte above the data blocks. Both arenas keep multiple terabytes below the 0x7FFF… user-space ceiling, and the mapping arena is now the only thing addressed from 0x7400, so a stray pointer into it is still recognisable by its address alone (the property the constant's comment always claimed and did not have).

Verified, two observations. The reservation-failure line disappeared and PPSA04263 went from 32 calls to 10,123 (+10,091), faulting far later at image+0x2ba47bc; a program cannot make ten thousand more calls without the map that failed now succeeding. Blast radius: PPSA25872 advanced 26,850 -> 39,929 calls (+13,079) as well, and PPSA21564 and PPSA02664 were unchanged (no regression). The now-visible 0x6b0000000000 conflicts on other titles are the guest's own hint address being refused and its allocator falling back to the arena as designed - non-fatal, and surfaced only because D462 now reports every reservation failure, not because this introduced one.