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

tools/test/smoke/strings/byte_ascii_smoke.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root=$(cd "$(dirname "$0")"/../../../.. && pwd)
+bin="$root/target/release/nyash"
+src="$root/apps/tests/strings/byte_ascii_demo.nyash"
+
+if [ ! -x "$bin" ]; then
+  echo "nyash binary not found at $bin; build first (cargo build --release)" >&2
+  exit 1
+fi
+
+export NYASH_VM_USE_PY=1
+unset NYASH_MINIVM_READ_STDIN || true
+out=$("$bin" --backend vm "$src" 2>/dev/null)
+want=$(printf "15\n5\nworld\n")
+test "$out" = "$want" || { echo "[FAIL] byte ascii smoke: expected\\n$want\\ngot\\n$out" >&2; exit 2; }
+echo "[OK] byte ascii smoke"

tools/test/smoke/strings/utf8_cp_smoke.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root=$(cd "$(dirname "$0")"/../../../.. && pwd)
+bin="$root/target/release/nyash"
+src="$root/apps/tests/strings/utf8_cp_demo.nyash"
+
+if [ ! -x "$bin" ]; then
+  echo "nyash binary not found at $bin; build first (cargo build --release)" >&2
+  exit 1
+fi
+
+export NYASH_VM_USE_PY=1
+unset NYASH_MINIVM_READ_STDIN || true
+out=$("$bin" --backend vm "$src" 2>/dev/null)
+want=$(printf "3\n1\n1\né𝄞\n")
+test "$out" = "$want" || { echo "[FAIL] utf8 cp smoke: expected\\n$want\\ngot\\n$out" >&2; exit 2; }
+echo "[OK] utf8 cp smoke"