feat(agent): add Requesty as an LLM provider

[Thibault Jaigu (Thibaultjaigu)]

Adds Requesty as an LLM provider, mirroring the existing OpenRouter provider. Requesty is an OpenAI-compatible LLM gateway that uses the same provider/model naming convention as OpenRouter (e.g. openai/gpt-4o-mini, anthropic/claude-sonnet-4-5).

Requesty is wired on the generic OpenAI-compatible path (createOpenAICompatible + a dedicated compatible-fetch), not the OpenRouter SDK, since it carries no OpenRouter-specific provider-routing bits.

Changes:

• apps/server/src/lib/requesty-fetch.ts — createRequestyCompatibleFetch() mirroring openrouter-fetch.ts: extracts detailed upstream errors and throws APICallError so the AI SDK's retry logic handles Requesty's transient 502s.
• apps/server/src/agent/provider-factory.ts and apps/server/src/lib/clients/llm/provider.ts — register the requesty provider (base URL https://router.requesty.ai/v1, apiKey, HTTP-Referer / X-Title attribution headers).
• packages/shared/src/constants/urls.ts — REQUESTY_API URL constant; packages/shared/src/schemas/llm.ts — REQUESTY added to LLM_PROVIDERS, the enum type, and the zod enum.
• apps/app/lib/llm-providers/* — provider type, template (base URL, app.requesty.ai/api-keys, docs.requesty.ai), form-schema enum, and an icon fallback (the pinned icon set has no Requesty glyph).
• Server and eval READMEs — Requesty added to the provider lists.

Testing: @browseros/server typecheck passes (exit 0); none of the edited files produce type errors. Live-verified: a chat/completions call to https://router.requesty.ai/v1 with openai/gpt-4o-mini and the attribution headers returned successfully.

Notes:

• The models.dev catalog (models-dev-data.json) is generated from an upstream that does not list Requesty, so it is intentionally not edited here.
• The pre-existing @browseros/app typecheck errors are missing generated GraphQL modules (@/generated/graphql/*), unrelated to this change.
• I understand a CLA may be required — happy to sign it.

Docs: https://requesty.ai · https://docs.requesty.ai · https://app.requesty.ai/api-keys · https://app.requesty.ai/router/list

I work at Requesty. This mirrors the existing OpenRouter provider as closely as possible. Happy to adjust or close it if it's not a fit.

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