Clarify native BTC perpetual identity, account-mode applicability and rule-version binding #332

Hello maintainers,

I am specifying a native BTC perpetual integration and would appreciate an authoritative documentation pointer for its product/account-mode boundary before assuming a particular configuration.

The proposed model is one native (validator-operated) BTC perpetual position with nominal USDC collateral, using standard account abstraction and cross-position margin. This is a proposed model, not a claim that these choices apply to an existing account. I want to distinguish account abstraction from position margin mode.

1. Product identity and currency roles: Which documented product identifier and read-only response fields identify this native BTC perpetual, distinguish it from other BTC-named markets, and establish its quote and collateral denominations?

2. Mode applicability and observation: Is the proposed combination of standard account abstraction and cross-position margin supported for that exact product? Which documented read-only fields establish an account's actual abstraction mode and the position's margin mode? Please identify unsupported combinations or relevant exceptions rather than assuming an account's configuration from the product name.

3. Applicable rules over time: How can a consumer identify the product/account rules applicable to an observation? Is an effective block height/time, schema/rule version, or documented change history available for changes to those identities and supported modes? If no such version binding is exposed, an explicit statement of that limitation would also help.

A citable specification or dated clarification stating the applicable mainnet/product scope would be useful. I am asking about the public contract and supported configuration, not requesting inspection of any account or asking for private account information.

This question is separate from #330 (public trade identity/replay) and #331 (book ordering/aggregation). It does not ask for funding formulas, margin calculations, performance advice or approval of a trading strategy.

Thank you.