OnSched 3.7.7 - availability cache and audit docs

API

• Availability cache freshness: Resource OAuth callbacks, weekly availability updates, and location association changes now clear affected availability caches only after their database transactions commit. This prevents stale slot responses when a write rolls back or when cache invalidation races the database commit.
• Appointment audit docs: Added a guide for GET /v3/appointment/{id}/audit, including filters, response shape, and PII-safe snapshot expectations for support tooling.
• External calendar sync docs: Clarified syncExternal=true behavior when a provider or OAuth issue prevents one connected calendar from refreshing. Incomplete syncs bypass cached availability for that response while previously stored external busy blocks remain in effect.