fix(audit): align workflow run Phase 3E contract

[KilianBoute]

Description

This change aligns the workflow-run audit contract with the Phase 3E ownership and retention model used by the latest workflow stack.

The previous contract still referenced obsolete grouping indexes, transitional rollback naming, and outdated runtime compatibility floors. That created a mismatch between what the audit tooling validated and what newer workflow services actually write and depend on.

This update brings the adapter and index inspection logic in sync with the current workflow-run schema by:

• updating runtime compatibility requirements to the finalized writer/reader versions
• standardizing legacy ownership handling on userid
• replacing deprecated grouping index expectations with the retention indexes now required by cleanup and status query flows
• validating canonical, legacy, and global retention index families explicitly
• documenting the new contract and migration expectations in the README and migration reference
• extending tests to lock the runtime floors and index expectations in place

As a result, audit output now reflects the real operational contract for workflow runs, reducing false positives during migrations and ensuring retention, cleanup, and project-scoped status queries are validated consistently across services.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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