- Remove `provider` and `metadata` fields from Bedrock request body.
Bedrock returns 400 ValidationException for unknown top-level fields.
- When filtered beta tokens list is empty, delete any pre-existing
`anthropic_beta` field in body to prevent client-injected tokens
from leaking to Bedrock unfiltered.
- Add `context-management-2025-06-27` and `fine-grained-tool-streaming-2025-05-14`
to bedrockSupportedBetaTokens whitelist per AWS documentation.