chore(upgrade-skills): record TML-2817 incidental extension substrate change

TML-2817 touched packages/3-extensions/mongo/src/contract/define-contract.ts
as part of a cast elimination refactor. No extension API or behaviour change;
changes: [] records the incidental diff.

Signed-off-by: Will Madden <madden@prisma.io>

Author: wmadden

skills/extension-author/prisma-next-extension-upgrade/upgrades/0.12-to-0.13/instructions.md

@@ -12,4 +12,9 @@ strings to `{ namespace, model }` objects. Extension authors only feel
 this if they hand-construct contract IR; the public framework
 factories (`createNamespaceTable`, `crossRef`, etc.) and the
 contract-builder produce the new shape directly. No codemod required.
+
+TML-2817: internal refactor of @prisma-next/extension-mongo's
+defineContract wrapper to eliminate bare casts via a shared bound
+contract builder. No extension API or behaviour change; incidental
+substrate diff only.
 -->