8aec83f82e
Mechanical refactor, prerequisite to ADR-0026 PR 1. Frees the `User` name for the upcoming ADR-0026 model (UUID PK + FK to Person + lastSignInAt), which has materially different semantics from the ADR-0020 user-directory cache. Zero behavioural change. Same columns, same indexes, same constraints, same call sites - just a different identifier on the model, the table, and the corresponding Prisma client field. Two renames in user-directory.service.ts: the Prisma model rename collided with an existing TS interface also called UserDirectoryEntry (which was actually the input shape of recordSignIn). The interface gets renamed to RecordSignInInput at the same time, which is its correct semantic name. Net effect: clearer on both sides. Postgres ALTER TABLE RENAME does NOT cascade to PK constraint / index names; the migration explicitly ALTER INDEXes the three named indexes (pkey + last_seen_at + username). The class name AdminUsersReader, the endpoint URL /api/admin/users, the DTO AdminUserDto and the local interface UserRow are unchanged - these are SPA/HTTP-facing identifiers where the "admin user list" URL semantics hold regardless of the backing table name.