RFC: separate confirmed interaction, finance domain and venue adapters

[huangruiteng]

This RFC defines the three-layer boundary for user-confirmed domain operations:

• public LoopX owns provider-neutral confirmation identity, immutable operation binding, frontend/Lark projection, and original-conversation result delivery;
• an optional finance execution package owns order terms, preflight, account-wide reservations, and financial outcomes;
• independently installed Aqua/Hyperliquid/Futu adapters own platform-specific products, precision, credentials, submission, and reconciliation.

The existing research providers remain read-only. This PR adds no runtime, trading permission, credential path, or UI behavior. It is a design proposal for the first complete simulated vertical slice, with frontend and Lark acceptance required before any live adapter.

The RFC now includes a semantic Chinese mirror and reciprocal links. The RFC template and docs governance smoke require future RFCs to provide a same-basename .zh-CN.md mirror; a small explicit legacy allowlist documents pre-rule RFCs.

Validation:

• python3 -m py_compile examples/docs-governance-smoke.py
• dedicated RFC mirror check passed;
• git diff --check passed;
• full examples/docs-governance-smoke.py remains a repository-wide check and is not claimed green from this focused change.

No frontend build is applicable because this PR changes documentation and governance validation only. Keep draft for maintainer review; do not self-merge.