Selecting a saved custom provider now switches instantly without
probing /models — the model name is stored in the config entry
as a complete profile (name + url + key + model).
Changes:
- custom_providers entries now include 'model' field
- Selecting a saved provider with a model just activates it
- Only probes /models if no model is saved (first-time setup)
- Menu shows saved model name: 'Local (localhost:8000) — llama-70b'
- Dedup on re-entry: still activates the model, just doesn't add
a duplicate config entry (updates model name if changed)
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