OCI — Digest-Based Incremental Sync (issue 11 of 29)

Labels: ready-to-code
Depends on: Issue 1 (#4039 shared infra), Issue 9 (#TBD core connector)
RHIDP Stories: RHIDP-15298
Feature: RHDHPLAN-1507 — Epic RHIDP-15294

Implement digest-based incremental sync: cursor storage schema (registryId, namespace, tagDigestMap, lastSync), tag-to-digest comparison detecting new/changed/removed tags, change detection algorithm translating to add/update/delete entity mutations, full refresh fallback for invalid cursors, and in-memory digest cache with 5-minute TTL and disk persistence.

Tasks

From openspec/changes/oci-skill-registry/tasks.md group 5 (RHIDP-15298):

• 5.1 Define cursor storage schema
• 5.2 Implement cursor persistence layer
• 5.3 Implement tag-to-digest comparison logic
• 5.4 Implement change detection algorithm
• 5.5 Implement full refresh fallback
• 5.6–5.7 Unit tests and performance test for incremental sync

From openspec/changes/oci-skill-connector/tasks.md group 3 (RHIDP-15326):

• 3.1 Implement in-memory digest cache
• 3.2 Implement 5-minute TTL on cache entries
• 3.3 Implement digest comparison logic: detect added, changed, removed skills
• 3.4 Implement delta mutation emission via applyMutation({ type: 'delta' })
• 3.5 Implement full mutation on first sync
• 3.6 Implement disk persistence
• 3.7 Implement disk cache loading on startup
• 3.8 Implement cache re-validation after TTL expiration
• 3.9–3.10 Unit and integration tests for cache logic

Specifications

• openspec/changes/oci-skill-registry/specs/digest-based-sync/spec.md
• openspec/changes/oci-skill-connector/specs/incremental-sync-scale/spec.md

Start with openspec/changes/oci-skill-registry/specs/digest-based-sync/spec.md and openspec/changes/oci-skill-connector/specs/incremental-sync-scale/spec.md, then review the referenced task groups. Implement and test cursor persistence, digest comparison, cache expiry and persistence, delta mutations, and full-sync fallback as specified; completion is covered by the requested unit, integration, and performance tests.