fix(ui): Add favorites and improve UI

[JamesDAdams]

Summary

• Adds a model favorites system to the ProviderSelector dropdown and new display settings for the model selector. Users can heart-toggle models to pin them as favorites, which appear in a dedicated "Favorites" section at the top of the dropdown. Three new settings in Settings > Display > Model Selector control dropdown height (Default / Full height), and whether favorites and providers start collapsed.

• Server-side pruning automatically removes orphaned favorites when providers or models are deleted. Also fixes a zustand infinite render loop caused by JSON.parse in a selector, a provider collapse bug on model load, and the dropdown top being hidden behind the header.

• Provider Selector UI Cleanups:

  • Prevent displaying the underlying backend subtitle (e.g. OpenAI) below provider names when the provider is a plugin (authAdapter or transportAdapter defined).

  • Compact the Connected / Connect badge button and align it further to the right in the provider action buttons row.

  • Fix styling and spacing in ProviderSelector.tsx alongside favorites and model dropdown enhancements.

AI-Enhanced Development

Tell what models helped shape this PR:

• AI Models: Claude Opus 4, Gemini 3.7 Flash

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Cache Impact

Does this PR affect anything cached — system prompts, tool definitions, skills, or other context?

• No

[co-l]

Merged, will be released in v2.0.136

AI-summary

• Rebased the PR onto latest develop and resolved 5 conflicts, including porting the settings layer from the retired zustand store (web/src/stores/settings.ts) to the new resource-cache hooks (useSetting, SETTINGS_KEYS in lib/resources)
• Translated all new UI strings (en + fr) and updated both test suites to mock the new settings hooks; fixed a test-order state-pollution bug in the settings mock
• Verified the full unit suite (5096 passed), typecheck, lint, format and duplicate clean, plus provider e2e green
• Pushed the ported branch to the contributor's fork so the PR merges cleanly
• Squash-merged