postMensaje fails silently when credentials are missing; callers have no way to know the message wasn't sent.
Non-null assertion on conv.clienteId could crash if clientId is null (e.g., new client flow bug); add guard or handle gracefully.
Comparing lowercased input with lowercased email is correct but redundant since 'lower' is already lowercased; simplify.
Using findFirst for telefonoNorm which should be unique; use findUnique with proper unique index for clarity and performance.
Unsafe cast 'as unknown as Prisma.InputJsonValue' bypasses type safety; use proper JSON serialization or Prisma's JsonValue type.
Using ISO string as option id but elegirOpcion lowercases it; ISO strings contain uppercase letters (T, Z) causing mismatch when user types the letter.
Buttons only show first 3 mechanics while text lists all; users can't select mechanics beyond the first 3 via buttons.
Magic numbers 30 and 200 for days ahead and max slots; extract to named constants for clarity.
Mutating opciones array after listaConLetras returns it creates hidden side effect; assign ids during mapping instead.