Super Metroid v0.3.20 - shared native/HLE package

This stable release includes the owner-approved shared SNES runtime optimizations on current engine main.

• Windows x64 packages select the qualified native audio advancement and mixing, fused immutable-ROM reads, compact scheduling services and existing native row planner/center reuse.
• Adaptive widescreen, authored-room boundary clipping, minimap anchoring and the prior renderer fixes are preserved. Custom rendering and presentation enhancements remain opt-in.
• Other dependency pins and ordinary source-build defaults are unchanged. Other platforms keep their existing portable implementation selections.

The shared runtime was qualified against the representative SNES title bundle and accepted by the owner. The engine pin adds no runtime or generator changes beyond the qualified revision. This release does not change gameplay or claim a universal frame-rate gain. Package measurements are workload-specific and are not additive.

The separate v0.4.x enhancement prereleases are unchanged. Keep native SRAM saves and settings when updating. Host save states belong to their exact build. Supply your own supported ROM; downloads contain only the precompiled runtime and assets.