Reference architecture and license review

Reviewed projects and lessons (no third-party source was copied):

Project	License observed	Pattern adopted or rejected
HTTPX2	BSD-3-Clause	explicit sync/async pooled transport boundary
Pydantic	MIT	immutable typed queries/settings
yfinance	Apache-2.0	concise notebook ergonomics; rejected mutable global concurrency
AKShare	MIT	simple function discovery; rejected a broad unstable root surface
OpenBB	AGPL-3.0	provider/query/fetcher concepts only; dependency/code rejected
dlt	Apache-2.0	schema contracts and replay concepts; heavy dependency rejected
Kedro	Apache-2.0	catalog and modular pipeline concepts; dependency rejected
5j9/tsetmc	GPL-3.0	capability inventory only; code copying rejected
pytse-client	GPL-3.0	capability inventory only; code copying rejected
mahs4d/tsetmc-api	MIT	endpoint discovery lead only, independently verified
tse_tick	MIT	timestamp and tick-domain review
tse-market-data	MIT	dataset capability review

Medallion guidance informed materially distinct Bronze/Silver/Gold layers. Polars lazy scans and Arrow dataset patterns informed canonical frames and optional conversion. DuckDB’s Parquet/Hive projection and filter pushdown informed the optional SQL facade.