PHLEGM v9 r21 - SNES ActRaiser Mode 7 performance and transition diagnostics

Optimized Mode 7 host rasterization by incremental fixed-point affine stepping and per-frame palette lookup.
Corrected VMAIN word-address remapping, buffered VRAM reads, and read increment after low/high port based on VMAIN.
Added one-time explicit console diagnostic when a game enables $420C HDMA. Per-scanline HDMA is NOT implemented by this revision.
PPU/APU compiled definition execution and native CPU-host accelerator kernels are preserved.
ActRaiser ROM, runtime gameplay, Windows/Linux builds and actual FPS measurements have not been executed in this environment.
If the title still breaks, capture CONSOLE and COREDUMP at the transition, especially any $420C HDMA warning or SPC700 fault.
