aws_bedrock_embeddings: support Cohere input_type and v4 response

[squiidz]

Cohere embedding models on Bedrock require an input_type field
(search_document, search_query, etc.) to produce correct asymmetric
embeddings, and Cohere Embed v4 changed the response schema from
{"embeddings": [[...]]} to {"embeddings": {"float": [[...]]}}.

Dispatch the request body shape and response parsing on the model ID,
using a substring match on "cohere" so regional inference profiles
like us.cohere.embed-v4:0 are detected. Both v3 and v4 response
shapes are now accepted. Titan model code paths are unchanged

[claude]

Commits
LGTM

Review
Single-commit PR adding Cohere input_type support and Cohere v4 response parsing to aws_bedrock_embeddings. Code paths are dispatched on a cohere substring match so regional inference profiles are handled; Titan paths are unchanged.

1. Test naming convention violation in internal/impl/aws/bedrock/processor_embeddings_test.go#L90-L134: six TestParseEmbeddingsResponse_* functions use underscore separators. The project test pattern explicitly requires camelCase ("Test function names use camelCase, not underscores").

[claude]

Commits
LGTM

Review
The PR adds Cohere model support (input_type field and v4 response schema) to the aws_bedrock_embeddings processor, including a substring-based model detection that handles regional inference profiles, and unit tests covering both v3/v4 response shapes and error cases. Configuration, error wrapping, license headers, and registration patterns all conform to the project conventions.

LGTM

[claude]

Test function names should use camelCase without underscores per the project's test conventions: write TestNewProcessorCohereRequiresInputType instead of TestNewProcessor_CohereRequiresInputType (the convention is "Write TestMyProcessorBadArgs, not TestMyProcessor_BadArgs").

[claude]

Commits

1. Commit aws_bedrock_embeddings: validate input_type for Cohere models at parse time — the message body states "Add a changelog entry for the Cohere request-shape fix", but no changelog file appears in this PR. Either include the changelog change or drop that claim from the message.

Otherwise commit granularity and message format are good.

Review

The Cohere request/response dispatch is clean and well-tested (request shape, v3/v4 response parsing, parse-time validation). One minor convention issue:

1. processor_embeddings_test.go#L142 — TestNewProcessor_CohereRequiresInputType uses an underscore; project test conventions require camelCase test names without underscores.