[codex] Prepare Python 3 p2pool runtime port

[turnkit]

Summary

• ports the Defcoin P2Pool codebase toward Python 3 runtime compatibility
• adds explicit bytes/text helpers and a modern Twisted HTTP helper
• ports the bundled ltc_scrypt extension to Python 3 build/module APIs
• fixes Twisted delayed-call cleanup and macOS memory sampling in the local test path

Validation

• python3 dev/python3_port_compile_check.py: 133 files, 0 compile failures
• git diff --check: clean
• Python 3.12 local suite: 79 tests passed

Deployment note

This is intentionally a draft. It should not be deployed to the live pool until the shadow-run plan passes against a Defcoin daemon and a controlled miner on alternate ports.