Internal Architecture & Memory Model

+--------------------+     +---------------------+     +--------------------+
| Unix Monotonic     | --> | Euclidean Day Count | --> | Formatted Buffer   |
| Clock (Epoch Sec)  |     | (Civil Date Math)   |     | (Zero-Alloc Stack) |
+--------------------+     +---------------------+     +--------------------+

1. Monotonic Ingestion: Captures epoch seconds directly from OS clock registers.
2. Euclidean Day Math: Computes Gregorian calendar dates using branchless integer arithmetic.
3. Stack Buffer Emission: Formats strings directly into fixed-size byte arrays.