fix(core): batch Polymarket position condition_ids gamma lookup

[atomzakk]

Chunk Gamma /markets enrichment in fetchPositions so wallets with 50+ historical positions no longer hit Cloudflare 403 HTML

[realfishsam]

PR Review: VERIFIED

What This Does

This changes Polymarket fetchPositions market-id enrichment to split Gamma /markets?condition_ids=... lookups into batches of 40. SDK consumers with wallets containing many historical positions should no longer hit a single oversized Gamma query that can be blocked by Cloudflare.

Blast Radius

Polymarket core only: core/src/exchanges/polymarket/fetcher.ts, specifically the private fetchRawPositions enrichment path from conditionId to Gamma market.id. No unified type, OpenAPI schema, SDK shim, router, or auth surface changed.

Consumer Verification

Before (base branch):
I built origin/main and ran a consumer-path harness that calls PolymarketFetcher.fetchRawPositions() with 81 positions and a local Gamma /markets mock that returns 403 when a request carries more than 40 condition_ids.

node /opt/data/cron/tmp/pmxt-pr-review/verify-polymarket-batch.js

Response snippet:

{"ok":false,"requestBatchSizes":[81],"error":"Request failed with status code 403","status":403}

After (PR branch):
The same harness against PR a032e51645a20f826ecf8962e49ec66430a7d647 succeeded and resolved all 81 market ids via three Gamma requests.

{"ok":true,"requestBatchSizes":[40,40,1],"count":81,"resolved":81,"sample":[{"conditionId":"cond-0","size":"1","avgPrice":"0.5","resolvedMarketId":"market-0"},{"conditionId":"cond-1","size":"1","avgPrice":"0.5","resolvedMarketId":"market-1"}]}

Test Results

• Build: PASS (npm run build --workspace=pmxt-core)
• Unit tests: PASS (npm test --workspace=pmxt-core: 24 passed, 1 skipped; 644 passed, 3 skipped)
• Server starts: PASS as part of root npm test verification script
• E2E smoke: PASS for the targeted Polymarket fetchRawPositions enrichment harness above; root npm test later failed in the Python SDK phase because /usr/bin/python3: No module named pytest in this environment, after core tests and server startup had already passed.

Findings

No blocking findings.

PMXT Pipeline Check

• Field propagation (3-layer): N/A — no unified fields added/removed.
• OpenAPI sync: N/A — no public method/schema signature changed.
• Financial precision: OK — no price/amount arithmetic changed.
• Type safety: OK — no new any beyond existing Gamma payload handling.
• Auth safety: N/A — no credential/signing path changed.

Semver Impact

patch -- bug fix for Polymarket position enrichment reliability.

Risk

The batch size is a fixed conservative constant (40) based on observed Cloudflare behavior; if Gamma later lowers its query-size threshold this could need another adjustment. Requests are sequential rather than parallel, so very large historical wallets may incur extra latency, but correctness improves and the affected path is private position enrichment.