Non-Functional Delta: YU07-historical-tick-store over YU06-eod-price-production

Req	Status	Notes
NFR-TS01 off the hot path	Done	No BLP/journal/order-matcher change; tick-store is an independent process consuming pre-existing broadcast subjects. Bench-compare not required (nothing on the order/tick path changed); per the parent handoff.
NFR-TS02 restart-safe, no publisher backpressure	Done	Both capture subjects are core-NATS broadcast (no ack semantics tying a publisher to tick-store's availability); a tick-store outage drops nothing for existing consumers and simply resumes capturing from whenever it reconnects.
NFR-TS03 bounded TAQ ingestion disk usage	Done	Streaming pipe design (research.md Decision 5); peak extra disk is one day's output Parquet partition, not the ~76.5GiB decompressed source CSV.
NFR-TS04 reuse proven libraries	Done	DuckDB (columnar storage + query) and unzip (archive streaming); no hand-rolled format or query engine.

Added later; the KDB-X analytical layer

Req	Status	Notes
NFR-TS05 tap never in the apply path	Done	The service thread allocates one record and does a non-blocking queue offer; a daemon thread does every file system call. A stalled disk fills the queue and drops; it cannot wedge apply.
NFR-TS06 drops counted and loud	Done	The first drop and every 10,000th log a WARN; stop() prints the totals, and that counter is the authoritative loss signal. .tx.gaps[] answers the narrower question from the other end; which consensus sequences produced no captured row; and is expected to be non-empty around control events.
NFR-TS07 bounded capture disk	Done	The tap stops capturing at KDB_TAP_MAX_MB (default 256) and says so. Analytics lose a tail; the Aeron Archive keeps its disk.
NFR-TS08 no authoritative state	Done	The capture log is a kdb tickerplant log, not a journal. Delete the whole directory and the cluster still recovers byte-identically; delete the Aeron Archive and it does not.
NFR-TS09 inert unless configured	Done	Unset KDB_TAP_DIR and the tap never starts; one null check per output event, the same shape as the two NATS bridges beside it.