refactor(predict): group expiry-market creation params into ExpiryTerms

[tonylee08]

Summary

• create_expiry_market passed the strike grid minimum, tick size, preallocation, fee window/multiplier, and leverage values through expiry_market::create_and_share and strike_exposure::new as a long list of same-typed, unlabeled u64s. Two of them could be swapped by accident with no compiler error.
• Added a public struct ExpiryTerms has copy, drop in strike_exposure holding the 8 immutable creation terms, plus an expiry_terms(...) constructor and an expiry_ms() getter.
• expiry_market::create_and_share now takes a single terms: ExpiryTerms instead of 6 numeric params, and no longer reaches into config.leverage_config() — it's a pass-through assembler.
• registry::create_expiry_market builds ExpiryTerms once (gathering the two leverage values alongside the grid/fee/expiry values it already collected) and passes the labeled value through both helpers. Its public signature is unchanged.

Key decisions

• ExpiryTerms lives in strike_exposure (the leaf), not in registry/expiry_market. Those are higher in the module DAG (registry → expiry_market → strike_exposure), so defining the struct there and having strike_exposure::new consume it would create a dependency cycle. The 8 values are exactly strike_exposure::new's inputs, so that's its natural home.
• Built once in registry, where every term is already gathered. This is what lets both helper boundaries pass a single labeled value rather than re-listing the numbers twice.
• One positional list remains — the strike_exposure::expiry_terms(...) constructor call in registry. Move only allows field-labeled struct literals inside the defining module, so the orchestrator can't write a labeled literal. This is down from two such lists before, and each argument there is a well-named local or a self-documenting config.leverage_config().*() call, reviewable in one place.
• Moving the two config.leverage_config() reads up into registry mirrors the existing pattern (registry already snapshots expiry_fee_window_ms/expiry_fee_max_multiplier from the Pyth feed config), so all creation terms are now gathered in one place.

Test plan

• sui move build --path packages/predict — clean, no errors or warnings
• sui move test --path packages/predict --gas-limit 100000000000 — 491/491 pass
• bunx prettier-move -c <changed files> --write — all files formatted
• Public create_expiry_market signature unchanged; its 3 registry test call sites unaffected