feat(amazon-bedrock): add Nova Web Grounding support

[huanshenyi]

Background

Amazon Bedrock announced Web Grounding support for Nova models, which provides a built-in tool for real-time web search capabilities.
This is a turnkey RAG option that allows Nova models to intelligently retrieve and incorporate up-to-date information with source
citations.

Reference: Build more accurate AI applications with Amazon Nova Web Grounding

Summary

This PR adds support for Nova Web Grounding in the Amazon Bedrock provider:

• Added BedrockSystemTool interface for system tool support in bedrock-api-types.ts
• Implemented nova_grounding tool definition in bedrock-nova-tools.ts
• Added Nova tool processing logic in bedrock-prepare-tools.ts to convert provider-defined tools to Bedrock's systemTool format
• Exported novaTools from the provider in bedrock-provider.ts and index.ts
• Added comprehensive tests (7 tests) in bedrock-prepare-tools.test.ts
• Updated documentation in amazon-bedrock.mdx with usage examples and availability information

Users can now use Nova Web Grounding like this:

import { bedrock } from '@ai-sdk/amazon-bedrock';
import { generateText } from 'ai';

const result = await generateText({
  model: bedrock('us.amazon.nova-premier-v1:0'),
  prompt: 'What are the current AWS Regions?',
  tools: {
    nova_grounding: bedrock.tools.nova_grounding(),
  },
});

Manual Verification

• ✅ Type-check: No type errors in new code
• ✅ Tests: All 7 new tests passing
• ✅ Lint: No lint errors
• ✅ Prettier: All source files properly formatted

Checklist

• Tests have been added / updated (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)
• A patch changeset for relevant packages has been added (for bug fixes / features - run pnpm changeset in the project root)
• I have reviewed this pull request (self-review)

Future Work

• Support for other Nova models (currently Premier only) when AWS extends availability
• Support for additional regions (US East Ohio, US West Oregon) when they become available