What changed

• specialize the private region fingerprint builder for boolean, char, int, and long
• encode signed decimal digits directly into the existing FNV stream without boxing, temporary numeric strings, or arrays
• preserve the existing : separators and exact Objects.toString(value, "") character contract, including zero and all MIN/MAX boundaries
• add a focused independent-reference regression test for the complete primitive sequence

Why

A full table render computes hundreds of region/tile fingerprints. Primitive fields currently box and materialize temporary decimal strings before each per-character FNV pass. The new encoder packs reverse decimal digits into two local longs, then emits them in the original order; it handles Long.MIN_VALUE in the negative domain to avoid overflow.

This deliberately does not use the behavior-changing type-marker/binary encoding from the dirty development tree.

Validation

No Gradle, JMH, test, or server workload was run locally. GitHub Build/Test is the functional gate. This PR remains draft and must not merge until #60 and the base-owned region profile in #62 land, then #62's independent exact-FNV oracle and time/allocation A/B must report PASS_OPTIMIZED.