Add nes-py native optimization and vector APIs

[Kautenja]

Summary

• Adds PPU sprite/background batching, mapper direct-read paths, ML observation helpers, and CPU instruction batching.
• Adds native vector emulator, batch RAM reads, and explicit state snapshot APIs.
• Documents native runtime troubleshooting and restores MMC3 background tile caching behavior.

Validation

Focused Python, native, benchmark, and packaging checks are recorded in the branch completion logs for the related work items.

Notes

This PR targets master from the pushed p90 branch.