feat(openai): add custom model info configuration

Adds support for configuring custom OpenAI-compatible model capabilities and pricing, including:

Max output tokens
Context window size
Image/computer use support
Input/output token pricing
Cache read/write pricing

src/shared/api.ts

@@ -38,6 +38,7 @@ export interface ApiHandlerOptions {
 	openAiBaseUrl?: string
 	openAiApiKey?: string
 	openAiModelId?: string
+	openAiCusModelInfo?: ModelInfo
 	ollamaModelId?: string
 	ollamaBaseUrl?: string
 	lmStudioModelId?: string