Harden and run 10M sharded Qdrant evidence

[CaspianG]

Scope

• bound sharded Qdrant upsert memory by streaming per-shard chunks
• resume completed checkpoints without regenerating vectors
• support per-shard gRPC ports and query timeouts
• apply scalar INT8 quantization and quantized search parameters
• refresh reproducible 10M and 100M sharded run plans

Validation so far

• 60 focused tests passed, 2 optional FAISS tests skipped
• real two-service Qdrant 1.18.2 smoke: recall@10 1.000, p99 5.59 ms
• complete checkpoint resume: no re-ingest, p99 6.90 ms

The strict 10M sharded artifact will be added after the full run completes.