pyvm: split op handlers into ops_core/ops_box/ops_ctrl; add ops_flow + intrinsic; delegate vm.py without behavior change

net-plugin: modularize constants (consts.rs) and sockets (sockets.rs); remove legacy commented socket code; fix unused imports
mir: move instruction unit tests to tests/mir_instruction_unit.rs (file lean-up); no semantic changes
runner/pyvm: ensure using pre-strip; misc docs updates

Build: cargo build ok; legacy cfg warnings remain as before

docs/comparison/nyash-vs-others.md

@@ -0,0 +1,26 @@
+# Nyash vs Other Languages — Feature Comparison
+
+Perspective
+- Nyash emphasizes a unified Box model, hygienic AST macros with sandboxing, and multi‑backend execution (PyVM/LLVM/Cranelift/WASM).
+
+Axes
+- Control Flow & SSA
+  - Nyash: explicit observability (hints), PHI hygiene invariants.
+  - Rust/Swift/Kotlin: SSA is internal; limited direct observability.
+- Exceptions
+  - Nyash: postfix `catch/cleanup` (scope‑first), zero‑cost lowering.
+  - Rust: Result/? idiom (no exceptions). Swift/Kotlin: try/catch/finally.
+- Macros
+  - Nyash: AST JSON v0, hygienic by construction, isolated child with capabilities.
+  - C: text macro. Rust: macro_rules!/proc‑macros. Lisp/Julia: homoiconic AST.
+- Scope
+  - Nyash: ScopeBox (compile‑time metadata) and ScopeEnter/Leave hints; disappears at runtime.
+  - Go/Rust/Swift: lexical scopes (no explicit observability layer).
+- Backends
+  - Nyash: PyVM (reference semantics), LLVM (AOT), Cranelift (JIT), WASM.
+  - Others: single backend or VM.
+
+Takeaways
+- Nyash’s differentiator is “observability without cost” and macro safety by default.
+- Where trade‑offs exist (e.g., temporary hygiene valves), they’re gated and documented.
+