Summary:
Backport of the **#31844 `yb_internal_conn`** stack to **2026.1**, bundled into one diff because the diffs are interdependent (the framework adds files the later diffs modify).
Original commits:
- 11e3be04c0537e782feeb99c956949a18b16b4b2 / D54156
- 8b8126b8f20dbbeed3e73ccc6abadf2ac5659120 / D53506
- 8cc33f76565330b56386baef08dc73ab8485d830 / D53799
- d8cada545783bebf57d57f90fc4c09c9784bfa45 / D53800
This replaces GitHub PR #32396, on which the DB test builds were not running. Conflict resolutions vs the original stack (branch divergence + #32398 "preload only the pg_rewrite list") were carried over from that PR.
Test Plan: Jenkins
Reviewers: sanketh, myang, #db-approvers
Reviewed By: myang
Subscribers: ybase
Differential Revision: https://phorge.dev.yugabyte.com/D55292