Remove confusing/outdated model recommendation copy from ModelPicker automatic-fetch hint

[awschmeder]

Description

The model picker's automatic-fetch hint (settings.modelPicker.automaticFetch) includes copy that recommends users select claude-sonnet-3-7 and look for "free models" on the server. This guidance is confusing, unactionable, and now outdated:

• It hardcodes a specific model recommendation into generic UI shown for all dynamic-model providers (LiteLLM, OpenRouter, etc.), which is misleading when that model is not present on a user's server.
• The recommended model, claude-sonnet-3-7, is discontinued, so the advice points users at a model that may no longer be available.
• The "free models" framing is unactionable: the model picker does not mark which models are free. It may display API cost after a model is selected, but this is not guaranteed across providers, so a user has no reliable way to act on the suggestion from within the picker.
• Steering first-time users toward free models is also questionable advice: free models often perform poorly and can produce a poor first-time user experience.

Proposed Change

Remove the recommendation sentence from the automaticFetch hint while preserving the functional portion of the hint (that models are fetched automatically). Update the English source string, all 17 additional locale files, and the ModelPicker.tsx Trans interpolation to drop the now-unused defaultModelId / defaultModelLink placeholders.

Affected Areas

• webview-ui/src/components/settings/ModelPicker.tsx
• webview-ui/src/i18n/locales/*/settings.json (18 locale files)

[awschmeder]