[Go] [Vertex AI] [Google AI] Document-based grounding support

[apascal07]

Describe the bug
Controlled here in ModelInfoSupports:

genkit/genkit-tools/common/src/types/model.ts

Line 122 in 96aa4d8

context: z.boolean().optional(),

Example middleware in JS:

genkit/js/ai/src/model/middleware.ts

Line 197 in 96aa4d8

export function augmentWithContext(

Some models support native document-based grounding, some do not. We need to add native support where supported and implement simulated support by injecting generation request docs into the prompt.