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.

plugins/nyash-json-plugin/src/constants.rs

@@ -29,4 +29,4 @@ pub const JN_FINI: u32 = u32::MAX;
 
 // Type IDs (for Handle TLV)
 pub const T_JSON_DOC: u32 = 70;
-pub const T_JSON_NODE: u32 = 71;
+pub const T_JSON_NODE: u32 = 71;