Search transit crossings of fixed reference-chart house cusps

Calculates Equal or Whole Sign cusps once from a known reference birth, then searches selected apparent-geocentric transit bodies for directed crossings of those fixed boundaries. This is a transit-through-reference-houses calculation, not continuously moving mundane houses. Placidus and Porphyry are excluded pending specialist acceptance. UTC dates 1800–2200; whole-second start-inclusive/end-exclusive intervals span at most 31 days. Exact crossing times are rounded to one second from a fixed 0.05-second numerical tolerance; neither is a physical accuracy guarantee. No interpretations, arbitrary targets, caller kernels, URLs, search tuning, or automatic retries. Each admitted request reserves one standard monthly quota unit before route validation or engine work; failed or timed-out admitted attempts are not refunded. Historical mode uses an explicit BCE/CE date object and UT1 conventions. Its response is the versioned historical envelope, not the modern UTC envelope. Read result for calculation fields and metadata for limits and uncertainty.