feat: Add FuturMix as an AI provider

[FuturMix]

Is your feature request related to a problem? Please describe.

Users who want to access multiple AI models (Claude, GPT, Gemini, DeepSeek) through a single API endpoint currently have limited gateway options in Roo Code. FuturMix provides a unified AI gateway with 22+ models, 99.99% SLA, and OpenAI-compatible API — similar to how OpenRouter and Requesty are already integrated.

Describe the solution you'd like

Add FuturMix as a native provider in Roo Code, following the same pattern as existing gateway providers (OpenRouter, Requesty, Vercel AI Gateway). The implementation would:

• Extend base-openai-compatible-provider.ts
• Add provider type definitions in packages/types/src/providers/futurmix.ts
• Add API handler in src/api/providers/futurmix.ts
• Add UI component in webview-ui/src/components/settings/providers/FuturMix.tsx
• Support dynamic model fetching via /v1/models endpoint
• Default base URL: https://futurmix.ai/v1

Describe alternatives you've considered

Users can use the "OpenAI Compatible" provider with a custom base URL, but a native integration provides:

• Curated model list with correct context windows and pricing
• Dynamic model discovery
• Proper provider branding in the UI
• First-class documentation

Additional context

• API: OpenAI-compatible (/v1/chat/completions), also supports Anthropic Messages format (/v1/messages)
• Models: 22+ models including Claude 4 Opus, GPT-4o, Gemini 2.5 Pro, DeepSeek
• Features: Auto-failover, load balancing, 99.99% SLA
• Website: https://futurmix.ai
• Docs: https://futurmix.ai/docs

I'm happy to implement this PR myself. The implementation would follow the Requesty/Unbound pattern (extend BaseProvider with OpenAI SDK).

[FuturMix]

Claiming this — I'll submit a PR for it.

[roomote-v0]

I've analyzed the codebase and here's a proposed implementation plan for adding FuturMix as a native provider, following the Requesty/Unbound pattern:

1. Type definitions - packages/types/src/providers/futurmix.ts

• Export futurmixDefaultModelId and futurmixDefaultModelInfo (with appropriate model defaults)

2. Provider types registration - packages/types/src/providers/index.ts

• Export from futurmix.ts, import the default model ID, add a case "futurmix" in getProviderDefaultModelId()

3. Provider settings schema - packages/types/src/provider-settings.ts

• Add "futurmix" to dynamicProviders array (since it supports /v1/models for dynamic model fetching)
• Create futurmixSchema with futurmixBaseUrl, futurmixApiKey, futurmixModelId fields
• Merge into discriminated union and combined schema
• Add futurmixModelId to model ID keys and MODELS_BY_PROVIDER

4. API handler - src/api/providers/futurmix.ts

• Extend BaseProvider, implement SingleCompletionHandler
• OpenAI SDK client with default base URL https://futurmix.ai/v1
• createMessage() / completePrompt() / fetchModel() / getModel() methods
• Register in src/api/providers/index.ts and add case "futurmix" in src/api/index.ts

5. Model fetcher - src/api/providers/fetchers/modelCache.ts

• Add case "futurmix" to fetch models from the /v1/models endpoint

6. UI component - webview-ui/src/components/settings/providers/FuturMix.tsx

• API key input, optional base URL override, model picker
• Wire into ApiOptions.tsx with case "futurmix"

7. i18n - Add translation keys for the FuturMix provider labels

8. Tests - Add unit tests for the handler and UI component

I noticed @FuturMix has claimed this issue and plans to submit a PR. Happy to defer if they're already working on it, or I can proceed with the implementation if that's preferred.

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.