hermes setup / hermes model used to silently skip the key prompt when
any value was present in .env — even a malformed paste — leaving users
with a stuck '✓' and no way to recover without hand-editing .env.
Replace the silent acknowledgement at all three API-key provider flows
(Kimi, Stepfun, generic) with a single [K]eep / [R]eplace / [C]lear
menu via a shared `_prompt_api_key` helper.
- K / Enter / Ctrl-C / unknown input → keep (never destroys the key)
- R → getpass for new key; empty input cancels and preserves existing
- C → clears the env var, tells user to rerun hermes setup, aborts flow
LM Studio's no-auth-placeholder substitution stays on first-time entry
only; on Replace an empty input means 'cancel', not 'overwrite with
dummy key'.
11 unit tests cover all branches incl. garbage-input-keeps-key, Ctrl-C
at the choice prompt, Replace-cancel preserving the old key, Clear
wiping only the target env var, and lmstudio placeholder semantics.
Fixes#16394
Reshapes #18355 — original PR pasted the menu inline at 3 sites with
no tests; this consolidates to one helper (+88/-66) with coverage.
Co-authored-by: Feranmi10 <89228157+Feranmi10@users.noreply.github.com>
