Register the six engram_geo_*_json operators in the compiler builtin_arity
table (bare heavy-runtime names + __ seed names, mirroring engram_activate_json)
and add the engram.el module wrappers, so a compiled El (CGI) program can call
them by name. The heavy-runtime C functions already existed (el_runtime.c:12287+,
declared el_runtime.h:627-632); this completes the EL call surface.
The shipped elc already emits a direct C call for these builtins (unknown
ident-calls pass through), so no self-host compiler fold — the memory-heavy,
drift-prone step — was required. Demonstrated end-to-end: a compiled geo_ops_demo.el
booted a copy of the store (13,036 nodes) and produced real subtract/distance JSON
on two real neighborhoods; test_geo_ops.c stays 20/20, ASan/UBSan clean.
Also brace the centroid_unit normalization if/else in engram_geometry.c to clear
the misleading-indentation warning (behavior-neutral).
will.anderson
85eee42106