feat(repository): implement user repository (#10967)

## Summary

This PR introduces the relational user repository for backend v3,
including schema, repository APIs, reducers/projections, and tests for
both human and machine users.

## What changed

* Added user-focused relational migrations (users, verifications,
metadata, PATs, machine keys, passkeys, identity provider links) and
related FK wiring.
* Implemented/expanded repository domain contracts and storage
implementations for human and machine user flows.
* Added support for machine secret handling and aligned access token
type modeling.
* Extended user domain models (verifications, password/email/phone/TOTP
state, passkeys, metadata, invite handling, identity provider links).
* Updated projection/reduction coverage and integration tests for key
user lifecycle events.
* Regenerated and updated mocks/enums plus supporting database
change/column utilities.

## Notes for reviewers

* This PR is large because it establishes the foundational relational
user storage layer and related test scaffolding. Sorry for that.

## Closes

Closes #10218
Closes #10224
Closes #10225
Closes #10209
Closes #10802

---------

Co-authored-by: Iraq Jaber <[email protected]>
Co-authored-by: Copilot <[email protected]>
Co-authored-by: Marco A. <[email protected]>
Co-authored-by: Tim Möhlmann <[email protected]>

backend/v3/storage/database/repository/repository.go

@@ -85,7 +85,9 @@ func updateOne[Target updatable](ctx context.Context, client database.QueryExecu
 	builder := database.NewStatementBuilder("UPDATE ")
 	builder.WriteString(target.qualifiedTableName())
 	builder.WriteString(" SET ")
-	database.Changes(changes).Write(builder)
+	if err := database.Changes(changes).Write(builder); err != nil {
+		return 0, err
+	}
 	writeCondition(builder, condition)
 
 	return client.Exec(ctx, builder.String(), builder.Args()...)