Replace deprecated AWS S3 manager dependency upstream

[lanycrost]

Summary

The engram dependency refresh to the latest released BubuStack packages keeps pulling github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.22.17 indirectly through shared runtime/storage dependencies. Go reports that module as deprecated and points to github.com/aws/aws-sdk-go-v2/feature/s3/transfermanager as the replacement.

We are intentionally keeping the latest currently-resolved version in downstream engrams for this release train, but this should stay in the bobrapet/core shared backlog so individual engrams do not carry one-off dependency workarounds.

Evidence

During the all-engram refresh after bubu-sdk-go v0.1.5, every engram retained this indirect dependency after go get -u all and go mod tidy:

github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.22.17 // indirect

The warning seen during module updates was:

go: module github.com/aws/aws-sdk-go-v2/feature/s3/manager is deprecated: superceded by feature/s3/transfermanager. See https://github.com/aws/aws-sdk-go-v2/discussions/3306

Affected downstream repos observed in this run include conversation-memory, http-request, json-filter, livekit-bridge, livekit-turn-detector, map-reduce-adapter, materialize, mcp-adapter, openai-chat, openai-stt, openai-tts, silero-vad, and text-emitter engrams.

Acceptance Criteria

• Identify the owning shared package/import path that pulls feature/s3/manager into BubuStack downstream modules.
• Replace usage with the supported AWS SDK transfer manager path where appropriate.
• Run the owning repo tests and at least one representative downstream go mod tidy/make test check.
• Avoid per-engram workaround commits unless the shared dependency migration requires follow-up cleanup.

Notes

This is not blocking the current engram SDK/action update cycle; keep it as backlog unless the dependency becomes a security or build issue.