Summary

Once transition-window writes are mirrored, the stable constituent contains the complete logical image during the active window. Simplify cursor and read routing without weakening transaction-level straddler protection.

Scope

• Stop opening ingest for leader reads solely because the step-down window is active.
• Continue using ingest for follower reads, window-created tables, and largest_key.
• Sample the step-down timestamp once per operation and use it consistently for routing and stable-open handling.
• Update snapshot, iteration, search, cached-cursor, restart, and boundary-read tests.
• Retain txn->stepdown_ts_set and the existing transaction-level straddler checks until the per-operation invariant work.