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/boxes_array.rs

@@ -0,0 +1,57 @@
+use super::*;
+use crate::box_trait::NyashBox;
+
+pub(super) fn try_handle_array_box(
+    this: &mut MirInterpreter,
+    dst: Option<ValueId>,
+    box_val: ValueId,
+    method: &str,
+    args: &[ValueId],
+) -> Result<bool, VMError> {
+        let recv = this.reg_load(box_val)?;
+        let recv_box_any: Box<dyn NyashBox> = match recv.clone() {
+            VMValue::BoxRef(b) => b.share_box(),
+            other => other.to_nyash_box(),
+        };
+        if let Some(ab) = recv_box_any
+            .as_any()
+            .downcast_ref::<crate::boxes::array::ArrayBox>()
+        {
+            match method {
+                "birth" => {
+                    // No-op constructor init
+                    if let Some(d) = dst { this.regs.insert(d, VMValue::Void); }
+                    return Ok(true);
+                }
+                "push" => {
+                    if args.len() != 1 { return Err(VMError::InvalidInstruction("push expects 1 arg".into())); }
+                    let val = this.reg_load(args[0])?.to_nyash_box();
+                    let _ = ab.push(val);
+                    if let Some(d) = dst { this.regs.insert(d, VMValue::Void); }
+                    return Ok(true);
+                }
+                "len" | "length" | "size" => {
+                    let ret = ab.length();
+                    if let Some(d) = dst { this.regs.insert(d, VMValue::from_nyash_box(ret)); }
+                    return Ok(true);
+                }
+                "get" => {
+                    if args.len() != 1 { return Err(VMError::InvalidInstruction("get expects 1 arg".into())); }
+                    let idx = this.reg_load(args[0])?.to_nyash_box();
+                    let ret = ab.get(idx);
+                    if let Some(d) = dst { this.regs.insert(d, VMValue::from_nyash_box(ret)); }
+                    return Ok(true);
+                }
+                "set" => {
+                    if args.len() != 2 { return Err(VMError::InvalidInstruction("set expects 2 args".into())); }
+                    let idx = this.reg_load(args[0])?.to_nyash_box();
+                    let val = this.reg_load(args[1])?.to_nyash_box();
+                    let _ = ab.set(idx, val);
+                    if let Some(d) = dst { this.regs.insert(d, VMValue::Void); }
+                    return Ok(true);
+                }
+                _ => {}
+            }
+        }
+        Ok(false)
+}