public: publish selfhost snapshot to public repo (SSOT using + AST merge + JSON VM fixes)

- SSOT using profiles (aliases/packages via nyash.toml), AST prelude merge
- Parser/member guards; Builder pin/PHI and instance→function rewrite (dev on)
- VM refactors (handlers split) and JSON roundtrip/nested stabilization
- CURRENT_TASK.md updated with scope and acceptance criteria

Notes: dev-only guards remain togglable via env; no default behavior changes for prod.

src/backend/mir_interpreter/handlers/mod.rs

@@ -2,6 +2,9 @@ use super::*;
 
 mod arithmetic;
 mod boxes;
+mod boxes_array;
+mod boxes_string;
+mod boxes_map;
 mod calls;
 mod externals;
 mod memory;