feat: add Corti provider

[hccullen]

Adds Corti — a first-party lab serving frontier reasoning models on sovereign EU infrastructure through an OpenAI-compatible API.

Provider

Endpoint	https://ai.eu.corti.app/v1 (/chat/completions, /models)
SDK package	@ai-sdk/openai-compatible
Env	CORTI_BEARER
Docs	https://docs.corti.ai

Models

Both are first-party inline definitions (no base_model). Corti is the lab that builds and serves these models.

Model	Reasoning	Effort	Context	Max output	Input	Output	Cache read	Modalities
corti-s1	always-on	high, max	262,144	16,384	$2	$8	$0.20	text → text
corti-s1-mini	always-on	none	262,144	16,384	$1	$4	$0.10	text+image → text

Reasoning is returned in the reasoning field of chat completions (interleaved = true) and as type: "reasoning" output items in the Responses API. The -instant variants (no reasoning) and other models from the API are not included in this PR.

Validation

• bun validate passes

Data sources

• GET https://ai.eu.corti.app/v1/models (live, no auth required)
• https://docs.corti.ai/models/models
• https://docs.corti.ai/api-reference/corti-models/models/list-available-models

[github-actions]

No actionable findings.