## Background
Bedrock's Anthropic integration needs specific beta flags for tool
search tools (`tool_search_tool_regex_20251119` and
`tool_search_tool_bm25_20251119`), but the upstream `@ai-sdk/anthropic`
package doesn't set them since they aren't needed for direct Anthropic
API calls.

## Summary
                      
- Added `tool_search_tool_regex_20251119` and
`tool_search_tool_bm25_20251119` to `BEDROCK_TOOL_BETA_MAP` with the
`tool-search-tool-2025-10-19` beta value.

## Manual Verification
Tested tool search with deferred tool loading on Bedrock — requests now
include the correct `tool-search-tool-2025-10-19` beta.

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

n/a

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Felix Arntz <felix.arntz@vercel.com>