Add verified special-constraint promotion

[termoshtt]

Summary

• add detector-supplied witnesses for promoting regular equality constraints to exact one-hot constraints
• expose preview, single and atomic bulk promotion, and promotion-history audit APIs in the Rust and Python SDKs
• prevent restoring a promoted source while its one-hot target still exists
• regenerate Python stubs and API references, and document the new public API in the English, Japanese, and Rust release notes

Design

A promotion witness is an untrusted claim rather than an applicable mutation plan. OMMX re-verifies the complete structural condition against the current instance whenever the witness is checked or applied: the source must be an active equality constraint over exactly the declared binary variables, with a common finite nonzero linear coefficient and the matching constant. Approximate and nonlinear representations are rejected.

Only the private planning layer owns target-ID allocation and mutation details. Bulk promotion reserves explicit target IDs before allocating omitted IDs and applies the complete batch atomically. Promotion metadata remains on the removed source constraint, allowing the audit API to reconstruct and verify the relationship after lowering, partial evaluation, or a v2 round trip without extending the protobuf provenance schema.

Closes #1024