Use local dotnet-ef tooling and strict EF migration checks

AGENTS.md

@@ -13,4 +13,6 @@ Also see the other related technical documentation: TECH.md, REQUIREMENTS.md and
 - After every iteration, do a git commit with a brief summary of the changes as a commit message.
 - Keep changes small and commit often. If one iteration encompasses many smaller tasks with more than one commit, create a git branch and do the commits there. Let me review the branch before merging it back to master.
 - If you find unexpected changes in the code (deletions, changes, diff results that were not communicated), never revert them and never restore the old state. Assume that those changes happened with intent.
+- Never use `git restore`, `git checkout --`, reset commands, or equivalent rollback actions to discard local changes unless the user explicitly asks for that exact rollback.
+- If a required tool is missing (for example `dotnet-ef`), install/configure the tool (prefer repo-local setup such as `dotnet tool manifest`) instead of weakening validations or muting warnings. If installation is blocked, stop and ask before changing validation strictness.
 - After changing the database, if your build is blocked by a running dotnet process, feel free to kill the process and retry the operation once.