RDDT: add milvus slo latency buckets

RDDT: Add unittest BuildKit image and disable GitHub Actions

Introduce Dockerfile.unittest.buildkit to run `make unittest` (C++ and Go)
via internal CI without producing a runtime image. Disable auto-triggered
GitHub Actions workflows in this fork, including Claude Code review, so
they only run on workflow_dispatch.

Co-authored-by: Cursor <cursoragent@cursor.com>

Simplify

RDDT: Use roaring bitmap

RDDT: Use roaring bitmap

RDDT: Use roaring bitmap

RDDT: Use roaring bitmap

RDDT: Use roaring bitmap

RDDT: Use roaring bitmap

RDDT: Fix knowhere selector dispatch and num threads