flake-register: skip 10k HNSW benchmarks in -short/-race

[aksOps]

Locations:

• internal/vectorindex/hnsw_test.go:216 (skip 10k benchmark in -short)
• internal/vectorindex/hnsw_test.go:223 (skip 10k recall benchmark under -race)

Both cover scale benchmarks that time out under -race. Tracking to consider a dedicated perf workflow on nightly runners.

Owner: unassigned.

[aksOps]

Fixed by #75 (chore: scale-tag nightly + drop scale tests from PR CI). Test is now behind //go:build scale + runs in the new nightly workflow.