fix(polymarket): resolve inactive markets via CLOB slug and stop retrying deleted events

[YaroShkvorets]

Follow-up to #307. Stacked on #307: this PR targets that branch and contains only the follow-up commit. Merge #307 first; GitHub will then retarget this PR to main.

Problem

Gamma's /markets/keyset never returns inactive markets, whatever active/closed/archived filters are passed. Polymarket has many of these: unnamed negRisk placeholder slots like "Will candidate O be the next regional board…" or MLB NRFI markets. #307 fixed the enrichment pass. This PR fixes the two remaining problems:

1. Main pass: on-chain registrations of these markets failed with No market found for condition_id every cycle (104 distinct ids in a single prod run on 2026-10-07).
2. Deleted events: /events/keyset returns [] both on errors and for events that no longer exist, so a deleted event was retried forever and could pin the head of the enrichment queue, the same failure mode as fix(polymarket): use event-embedded markets in enrichment so placeholders don't stall the queue #307.

Fix

Main pass (fetchMarketFromApi): when keyset doesn't return a market, fall back to CLOB /markets/{condition_id} to get its market_slug, then Gamma /markets/slug/{slug} for the full market including events. The result is only accepted if its conditionId matches the one requested.

Enrichment (fetchEventFromApi): when keyset is empty, fall back to /events/slug/{slug}. A 404 returns 'not_found' and processEventEnrichment records the event as enriched (0 markets). Any other failure returns null and stays retriable.

A new fetchJson helper keeps a 404 distinct from other failures for single-object endpoints. fetchGammaApi is unchanged.

Verification

• Smoke test against the live Gamma and CLOB APIs: 104/104 condition ids failing in prod now resolve. A real event slug returns its 18 markets, and a fake slug returns 'not_found'.
• Brand-new markets that Gamma hasn't indexed yet still return null and are retried as before.
• Tests added: CLOB slug fallback, CLOB miss, slug resolving to a different condition (rejected), keyset hit skips the fallback; event keyset hit, slug fallback, 404 → 'not_found', 503 → null; deleted event recorded by the enrichment pass.
• bun test services/polymarket: 35/35 pass. The 9 hyperliquid failures also happen on main and are unrelated.

Note

fetchMarketsFromApi (batch) is now only used by its tests. Gamma's OpenAPI spec caps condition_ids at 100 per request, while KEYSET_PAGE_LIMIT is 1000, so it's worth checking if anything starts using it again.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The fallback paths are validated, preserve retry behavior for transient failures, and have focused test coverage.

0 open findings

What changed in this PR

Adds reliable fallbacks for inactive Polymarket markets and deleted events.

Changes:

• Resolves omitted markets through CLOB and Gamma slug endpoints.
• Distinguishes deleted events from transient API failures.
• Adds fallback and enrichment tests.

File	Description
services/​polymarket/​gamma.ts	Adds market and event fallback lookups.
services/​polymarket/​index.ts	Records deleted events as enriched.
services/​polymarket/​index.test.ts	Tests deleted-event enrichment.
services/​polymarket/​fetch-gamma.test.ts	Tests fallback API behavior.

🧠 Review effort: Balanced

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