feat: prime order metadata caches through the public getters

[kartojal]

Alternative to #106 that adds no new public method. #106 stays open for comparison.

• getVersion() adopts the fetched order version for later orders on the client and joins a version request that is already in flight. An error response adopts the default version 2 as before.
• getClobMarketInfo() shares one in-flight request per condition. It already primes the tick size, neg-risk, and fee caches for both outcomes.
• Concurrent orders share one in-flight version request. A refresh after an order version mismatch asks the server again.
• createAndPostOrder and createAndPostMarketOrder retry once only when the CLOB rejected the order for a version mismatch, instead of when a version snapshot changed. This closes a double-post path and also retries under throwOnError before surfacing the ApiError.
• Order creation rechecks the fee cache after resolving a token, so a market fetch that landed meanwhile is not repeated.
• README documents the two-call recipe for warming these caches ahead of the first trade.

Release notes: calling getVersion() now also sets the version used to sign later orders on that client. Under throwOnError, a version mismatch is retried once before it throws.

No version bump. The release commit sets it.

---

Note

Medium Risk
Changes order-post retry semantics and version/market metadata caching on the trading path; incorrect retry logic could duplicate posts or leave orders on wrong exchange versions.

Overview
getVersion() and getClobMarketInfo() now prime per-client caches used when signing orders: version is stored on success (default 2 on soft failure), and market fetches refresh tick size, neg-risk, and fees for both outcomes. Concurrent callers share one in-flight /version or per-condition CLOB market request instead of duplicating GETs.

Create-and-post flows change how migration recovery works: createAndPostOrder / createAndPostMarketOrder retry once only when the CLOB returns an order version mismatch, including under throwOnError, instead of re-posting whenever a version snapshot changed between attempts (closing a double-post path). Forced refreshes after mismatch clear stale in-flight version requests. Token resolution skips a redundant market fetch if warm-up filled fee caches meanwhile.

The README documents a two-call warm-up (getVersion + getClobMarketInfo) before the first trade. New orderMetadataCache.test.ts covers cache priming, refresh, deduplication, failure modes, and mismatch retries.

^{Reviewed by Cursor Bugbot for commit a24bc4f. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 2 potential issues.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, have a team admin enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit a260eb1. Configure here.}