Ported the Any-boxing conversion pair:
- box_any: alloc the 16-byte { type_tag@0, value@8 } box, tag = source TypeId
index (matches the legacy comptime interp; runtime anyTag also normalizes
arbitrary-width ints). Value slot holds a word source's scalar bytes (via
writeField(source_type) so f32 round-trips) or an aggregate source's
flat-memory ADDR (the runtime pointer-in-value-slot shape).
- unbox_any: read the value slot back (word -> readField; aggregate -> the
stored ADDR).
Required promoting .any to a first-class flat-memory aggregate (was
kindOf -> .unsupported): kindOf(.any) = .aggregate (16B, by-address) and
fieldOffset special-cases .any to the {@0, @8} layout (shared with
string/slice). Without the latter a struct_get on an Any panicked
(union field 'struct' while 'any' is active) -- caught + fixed, no crash.
Updated two unit tests that used unbox_any as the "unported op" example ->
compiler_call; added a box->unbox round-trip test. 697/0 both gates + all
unit tests. The 6 box_any examples no longer bail at box_any (output matches
legacy) but fall back further at switch_br/type_name/out (later 4A steps).
1526d198e2