fix(diarize): expose diarize_model so the v2 diarizer is reachable at all

[Jacob-Lasky]

The params panel could not produce the v2 diarizer by any path.

diarize is a deprecated boolean that always routes to v1. diarize_model is the current parameter and both enables diarization and selects the version, so it must be sent without diarize. The panel instead offered the legacy diarize_version select gated behind x-if="params.diarize" — so the only way to see the version control was to enable the thing that forces v1.

Confirmed on the wire, against production

diarize=true                              200, speaker labels (v1)
diarize_version=latest  (alone)           400  Failed to parse query string
diarize=true + diarize_version=latest     200
diarize_model=v2        (alone)           200
diarize_model=latest    (alone)           200
diarize=true + diarize_model=v2           400  diarize_model cannot be used together
                                               with diarize or diarize_version.
                                               (INVALID_QUERY_PARAMETER)
diarize_model=v2        on streaming      handshake rejected

Deepgram does not pick a winner between them — it rejects the pair outright. This is a mutual exclusion, not a precedence rule.

Changes

• UI models diarize_model (v1 / v2 / latest) instead of diarize_version, and the select is no longer gated behind the checkbox.
• The two controls clear each other, since sending both is a hard 400.
• Hints state that v2 is batch-only and that the checkbox means v1.
• clean_params drops diarize / diarize_version when diarize_model is present. The UI already prevents the pair; this covers the extra escape hatch and saved presets from before the rename, so an old config degrades to the modern parameter instead of a 400.
• The deprecated boolean still works alone — replicating a legacy customer config is a job this tool has.

diarize_model is one of the params deepgram-sdk 7 added, so it rides as a real connect() kwarg rather than through the passthrough. A test pins that.

Verification

Semantics confirmed via DeepHive against the Deepgram docs, then verified on the wire rather than taken on faith.

116 passed, 1 skipped. UI probe:

diarize_model select visible WITHOUT diarize checked: True
options: ['Off / use the deprecated Diarize checkbox', 'v1', 'v2 (batch only)', 'latest']
after select v2      -> diarize_model='v2'     diarize=False
after check diarize  -> diarize_model=''       diarize=True
after select latest  -> diarize_model='latest' diarize=False
URL preview: ...&diarize_model=latest&...   (no diarize param)
pageerrors: none