fix(sync): retain rollout replay ownership pin

[agarwal-ishaan]

Summary

• Authorize the immutable sync-rollout replay ownership digest separately from the mutable live digest.
• Preserve the historical protected transition after a live policy re-pin.
• Guard both digest pins and add a regression test that simulates a live re-pin.

Fixes #2383

Validation

• pytest tests/test_sync_core_pdd_rollout_policy.py -k sync_rollout_repair -q
• python -m compileall -q pdd/sync_core/manifest.py tests/test_sync_core_pdd_rollout_policy.py
• git diff --check