feat: add EID cache with per-source TTL

[MO-Thibault]

Summary

• Adds eidCache config option to the SDK constructor — when enabled, targeting() merges fresh EIDs with previously cached EIDs from localStorage, applying per-source TTL expiry
• Exports mergeWithCache() for wrappers using resolveMultiNodeTargeting (longitudeads, unwind, mediavine, weatherchannel)
• Dispatches optableResolved event on window and document for backward compat with existing Prebid RTD listeners

Why

8 SDK wrapper bundles in optable-solutions copy-paste ~143 lines of identical EID caching logic (dedupeAndManageCache, saveResults, dispatchOptableResolved). 4 more customer repos (longitudeads, unwind, mediavine, weatherchannel) have similar implementations with minor variations. This centralizes the core logic so wrappers just set eidCache: { enabled: true }.

Usage

new OptableSDK({
  host: "customer.cloud.optable.co",
  site: "my-site",
  eidCache: {
    enabled: true,
    ttl: {                                          // optional overrides
      'custom-source.com': 5 * 24 * 60 * 60 * 1000
    }
  }
});

For wrappers using resolveMultiNodeTargeting:

import { mergeWithCache } from '@optable/web-sdk';

const result = await resolveMultiNodeTargeting(rules);
const merged = mergeWithCache(result, { enabled: true });

Default TTLs (baked in, overridable)

Source	TTL
uidapi.com	1 day
id5-sync.com	7 days
default	3 days

Test plan

• 12 unit tests covering merge logic, TTL expiry, collision handling, malformed storage, custom keys
• 94% code coverage on eid-cache.ts
• TypeScript compilation clean
• Integration test with one wrapper bundle (arena — next PR)
• Staging deployment to verify enrichment rates hold

🤖 Generated with Claude Code

[jplaroche]

LGTM