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

apps/tests/macro/exception/expr_postfix_direct.nyash

@@ -0,0 +1,12 @@
+function f(x) {
+  return x
+}
+
+function main(args) {
+  local i = 0
+  loop(i < 2) {
+    f(i) catch(e) { print(e) } cleanup { print("cleanup") }
+    i = i + 1
+  }
+}
+

apps/tests/macro/exception/loop_if_join_postfix.nyash

@@ -0,0 +1,16 @@
+function f(x) {
+  return x
+}
+
+function main(args) {
+  local i = 0
+  local a = 0
+  loop(i < 2) {
+    // both branches assign to the same variable -> JoinResult(a)
+    if i % 2 == 0 { a = 1 } else { a = 2 }
+    // include postfix sugar to exercise TryCatch normalization in the same scope
+    with_cleanup(postfix_catch(f(i), "Error", fn(e){ print(e) }), fn(){ })
+    i = i + 1
+  }
+}
+

apps/tests/macro/exception/loop_postfix_sugar.nyash

@@ -0,0 +1,15 @@
+function f(x) {
+  return x
+}
+
+function main(args) {
+  local i = 0
+  loop(i < 2) {
+    with_cleanup(
+      postfix_catch(f(i), "Error", fn(e){ print(e) }),
+      fn(){ print("cleanup") }
+    )
+    i = i + 1
+  }
+}
+

apps/tests/macro/exception/postfix_catch.nyash

@@ -0,0 +1,9 @@
+// Phase 1 sugar: postfix_catch(expr, "Error", fn(e){ body })
+function do_work(args) {
+  return 0
+}
+
+function main(args) {
+  postfix_catch(do_work(args), "Error", fn(e){ print(e) })
+}
+

apps/tests/macro/exception/postfix_catch_method.nyash

@@ -0,0 +1,12 @@
+// Phase 1 sugar: method call wrapped by postfix_catch
+box Worker {
+  run() {
+    return 0
+  }
+}
+
+function main(args) {
+  local w = new Worker()
+  postfix_catch(w.run(), "Error", fn(e){ print(e) })
+}
+

apps/tests/macro/exception/with_cleanup.nyash

@@ -0,0 +1,9 @@
+// Phase 1 sugar: with_cleanup(expr, fn(){ body })
+function cleanup_target(args) {
+  return 1
+}
+
+function main(args) {
+  with_cleanup(cleanup_target(args), fn(){ print("done") })
+}
+