docs(codex): record Windows development handoff

[Mydstiny]

What changed

• Reconciled the shared handoff state with public main at c502221e3.
• Distilled Windows-only Codex memory into sanitized, platform-neutral development rules.
• Recorded API 23/ArkTS, DevEco/Hvigor, native/Rust ABI, FreeRDP/RustDesk, Opus, signing, hook and Git workflow requirements.
• Added 12 structured pitfalls with platform, root cause, repair, validation and long-term-rule status.
• Recorded Windows tool observations and explicitly marked Mac and real-device checks as pending.

Validation

• git diff --check passed.
• verify_open_source_release.ps1 -Mode Light passed.
• Workflow policy tests passed.
• Opus artifact location test passed.
• Pre-push public-history guard test passed.
• No runtime source or dependency files were changed.

Privacy boundary

No raw Codex memory, chat/session logs, secrets, signing contents, AGConnect values, local properties, device data, screenshots, logs or build artifacts are included.