Report Rohlík's "confirm your login by e-mail" (login status 202) as an actionable message instead of a generic error

[dvejsada]

Background

Rohlík's login endpoint can answer {"status": 202, "messages": [], "data": null} — the login was accepted but is not complete until the user clicks a link Rohlík e-mails them, so no session is issued. Their login page carries the matching copy ("Pro dokončení přihlášení klikněte na odkaz, který jsme vám poslali na adresu {{email}}" / "Zbývá jen potvrdit e-mail"), and they have magicLink → /magic-login/keep-account and /verification/email routes. Full analysis in #79.

This is account-level state on Rohlík's side, so it is not something the integration can satisfy itself — the user has to act in their mailbox.

Current behaviour

rohlik-api collapses this into a bare RohlikAPIError whose message degenerates to "Unknown error occurred during login: Unknown error", dropping the status code (upstream: dvejsada/rohlik_api_python#8).

• Config flow / reauth (config_flow.py:84, config_flow.py:147): except RohlikAPIError → cannot_connect → "Failed to connect to Rohlik.cz". Actively misleading — the connection is fine, and the user goes off debugging their network. On v0.5.0 the same case surfaced as "Neočekávaná chyba" (Neočekávaná chyba #79).
• Runtime (hub.py:476): RohlikAPIError → UpdateFailed, so a 202 on a re-login makes the integration retry forever and sit there unavailable, with nothing telling the user why.

What to do

Blocked on dvejsada/rohlik_api_python#8 landing (dedicated error type / status on the exception), then here:

1. Split the error mapping in the config and reauth flow:
   • InvalidCredentialsError → invalid_auth
   • APIRequestFailedError → cannot_connect (genuine network failures)
   • the incomplete-login error → a new login_not_confirmed string, e.g. "Rohlík.cz needs this login confirmed. Open the link Rohlík just e-mailed to your address, then try again." — added to both translations/en.json and translations/cs.json.
2. Handle it at runtime too, rather than retrying silently: raise a repair issue (homeassistant.helpers.issue_registry) carrying the same instruction, since this needs the user to do something outside Home Assistant. ConfigEntryAuthFailed is the alternative, but the reauth dialog asks for a password that is not the actual problem.
3. Keep a test for each mapping so the "cannot_connect" regression cannot come back.

Notes

The 202 semantics are inferred from Rohlík's frontend, not from documentation — see #79 for exactly what is verified (including that the request shape is not the cause: a cookie-less POST with the library's User-Agent returns a proper 401 for bad credentials). Worth confirming against a real 202 before shipping the user-facing wording.