feat(pylon): consume canonical Dynamo stats streams

[barrygreengus]

Summary

• translate between the Stargate tunnel contract and Dynamo request metadata without sending Stargate/Pylon IDs upstream
• consume the KVDCRelay load and KV-usage gRPC streams and project canonical model/load/cache stats into Pylon registrations
• advertise models observed from only one source as inactive and fail closed when the required relay stream is unavailable
• preserve opaque passthrough behavior for non-Dynamo upstreams

Depends on ai-dynamo/dynamo#13187.

Validation

• cargo fmt --all -- --check
• cargo test --workspace --quiet
• cargo clippy --workspace --all-targets -- -D warnings

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🛡️ CodeQL Analysis

🚨 Found 5 issue(s)

Severity Breakdown:

• 🔴 Errors: 0
• 🟡 Warnings: 0
• 🔵 Notes: 0

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_{🕐 Last updated: 2026-08-27 21:07:27 UTC | Commit: 1920685}