Change access_token and refresh_token to Text type

[err0rgod]

Changed access_token and refresh_token columns to use Text type for better handling of larger strings.

When using OAuth2 providers such as Authentik with RS256-signed access tokens, the access_token (and sometimes refresh_token) exceeds 1024 characters. This results in a StringDataRightTruncation error in PostgreSQL:
psycopg.errors.StringDataRightTruncation: value too long for type character varying(1024)

1. Increased access_token and refresh_token field lengths from 1024 to Text type.
2. Verified behavior against PostgreSQL using long RS256 tokens.
   3.All tests pass with 100% coverage.