:sig
StringMap array_merge(StringMap a, StringMap b)
DValue array_merge(DValue a, DValue b)

:params
a : left-hand source map or tree
b : right-hand source map or tree
return value : merged result

:see
>types
0_DValue
0_StringMap
json_decode

:content
Merges two maps or trees using PHP-like merge behavior.

For `StringMap`, keys from `b` overwrite keys from `a`.

For `DValue`, string keys from `b` overwrite keys from `a`. Numeric keys are appended and reindexed when either side behaves like a list.

This helper is the closest UCE equivalent to PHP `array_merge()` for common request, config, and JSON-shaped data.

:example
StringMap left;
left["name"] = "Ada";
StringMap right;
right["role"] = "admin";
StringMap merged = array_merge(left, right);
print(merged["name"], " ", merged["role"], "\n");