[mstan]

The custom renderer reads captured register values but allocates complete mutable PPU temporaries for them. Use the shared 64-byte register type and pure raster jobs from framework PRs 221/222. This is a mechanical adapter change: scene reconstruction, assets, cameras and rendering algorithms remain in place. The new engine pin also gives the shared scene exporter bounded scratch lifetime.

Stacked on MMX PR 149. Existing renderer and elective optimization defaults are unchanged; background spans remain default OFF. Both matched qualification arms retain the existing native row/background-span package, with shared memory changes added only in the candidate.

Native/reference/row fixtures pass, including 1,536 scalar background rows and 512 composition rows. All four built Magic Carpet cases match baseline traces, as do captured view/HUD checks. Current/fresh state, rewind/replay and rollback pass. Previously accepted boss-spawn qualification is reused after verifying unchanged fix/test blob identities. Qualified title head: 4fe87d3; engine: 8323d7813e356f549a12f50e3e12e5844956a273.

Five balanced pairs per stock/16:9 profile on the capacity-reserved PC/SERVER pool show small mixed CPU deltas: both profiles are neutral/inconclusive. Candidate BSS is 1,572,864 bytes smaller; paired median peak commit falls 1.61 MiB stock and 1.76 MiB wide. No CPU speedup or Xbox qualification is claimed. One combined owner gameplay check with Metroid/SMW and merge handoff remain. Raw samples, identities, settings and telemetry are retained in G:\Temp\Codex\snesrecomp\shared-render-registers-20261028\campaign-results.json.

Tracking: shared beads-8wg.2.167 / beads-8wg.2.168, campaign beads-2wy8.1. Keep draft until the combined gate is complete.