[TexasCoding]

Closes #563

Fixes the spec drift from Spec Drift run 41197408777. Minor (22.6.0): no public Python attribute or method was renamed or removed, and no new required request field was added.

What changed

• Klear margin money fields: the updated SCM spec adds *_fp fixed-point dollar strings next to the existing int64 *_centicents fields; the old fields are still in the spec. So the 13 affected models get new optional *_fp: DollarDecimal | None attributes, and *_centicents stays a plain int. (An earlier WIP commit aliased the two onto one attribute. That was reverted because it would have silently turned centicent ints into dollar Decimals.)
• margin.withdraw_settlement_balance (sync and async) now posts to POST /margin/settlement_balance_withdrawal. Method name and request/response models are unchanged.
• Small optional additions that only produced warnings: rfq_batch_id (RFQ, RfqCreated/RfqDeleted), orderbook snapshot/delta clock, UserOrdersPayload.last_update_reason, perps ExchangeStatus resume-time/index-statuses/intra-transfers fields (+ ExchangeIndexStatus), MarginMarket.market_id, IntraExchangeInstanceTransfer.client_transfer_id.
• Specs re-synced, METHOD_ENDPOINT_MAP and BODY_MODEL_MAP updated, regression tests added (centicents-only payloads, payloads with both names, serialization, new withdrawal path), CHANGELOG and docs/perps.md updated, version bumped to 22.6.0.

Blast radius (by hand, GitNexus isn't available)

• kalshi/perps/klear/models/margin.py: only additive optional fields. Existing attribute types are unchanged. Responses that leave out *_fp still parse.
• kalshi/perps/klear/resources/margin.py: only the URL path changed. Anyone still calling the old path directly would get a 404 upstream anyway, because Kalshi removed it.
• Core/WS/perps models (communications, portfolio, orderbook_delta, user_orders, exchange, markets): optional fields default to None. Models with extra="forbid" are response models only, so no request body changes.
• New export ExchangeIndexStatus in kalshi.perps. Additive.
• Nothing hand-edited under kalshi/_generated/.

Gates

• uv run ruff check .: pass
• uv run mypy kalshi/: pass (161 files)
• uv run pytest tests/ --ignore=tests/integration -q: 5062 passed, 3 skipped
• uv run pytest tests/test_contracts.py -W error::UserWarning: 930 passed