Stage-B: add --v1-compat opt-in path and smoke

tools/smokes/v2/profiles/quick/core/selfhost_stageb_v1_compat_vm.sh

@@ -0,0 +1,76 @@
+#!/bin/bash
+# selfhost_stageb_v1_compat_vm.sh — Stage-B emit via MirJsonV1Adapter opt-in canary
+
+set -uo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../.." && pwd)"
+fi
+HAKO_BIN_DEFAULT="$ROOT/tools/bin/hako"
+HAKO_BIN="${HAKO_BIN:-$HAKO_BIN_DEFAULT}"
+
+warn() { echo -e "[WARN] $*" >&2; }
+info() { echo -e "[INFO] $*" >&2; }
+pass() { echo -e "[PASS] $*" >&2; }
+fail() { echo -e "[FAIL] $*" >&2; return 1; }
+skip() { echo -e "[SKIP] $*" >&2; exit 0; }
+
+if [ "${SMOKES_ENABLE_STAGEB_V1:-0}" != "1" ]; then
+  skip "SMOKES_ENABLE_STAGEB_V1!=1; skipping Stage-B v1 compat canary"
+fi
+
+if [ ! -x "$HAKO_BIN" ]; then
+  warn "Hako binary not found: $HAKO_BIN (set HAKO_BIN to override)"
+  skip "hako binary missing"
+fi
+
+compile_stageb_v1() {
+  local code="$1"
+  local tmp_hako="/tmp/hako_stageb_v1_$$.hako"
+  local json_out="/tmp/hako_stageb_v1_$$.mir.json"
+  printf "%s\n" "$code" > "$tmp_hako"
+  local raw="/tmp/hako_stageb_v1_raw_$$.txt"
+  NYASH_PARSER_ALLOW_SEMICOLON=1 \
+  NYASH_SYNTAX_SUGAR_LEVEL=full \
+  NYASH_ENABLE_ARRAY_LITERAL=1 \
+  HAKO_ALLOW_USING_FILE=1 NYASH_ALLOW_USING_FILE=1 \
+  HAKO_PARSER_STAGE3=1 NYASH_PARSER_STAGE3=1 \
+  NYASH_VARMAP_GUARD_STRICT=0 NYASH_BLOCK_SCHEDULE_VERIFY=0 NYASH_PHI_VERIFY=0 \
+  NYASH_QUIET=1 HAKO_QUIET=1 NYASH_CLI_VERBOSE=0 \
+  "$ROOT/target/release/nyash" --backend vm \
+    "$ROOT/lang/src/compiler/entry/compiler_stageb.hako" -- --v1-compat --source "$(cat "$tmp_hako")" > "$raw" 2>&1
+  awk '/"version":0/ && /"kind":"Program"/ {print; exit}' "$raw" > "$json_out"
+  rm -f "$raw" "$tmp_hako"
+  if [ ! -s "$json_out" ]; then
+    warn "Stage-B v1 compat compilation failed"
+    rm -f "$json_out"
+    return 1
+  fi
+  echo "$json_out"
+  return 0
+}
+
+run_gate_c() {
+  local json_path="$1"
+  NYASH_QUIET=1 HAKO_QUIET=1 NYASH_CLI_VERBOSE=0 NYASH_NYRT_SILENT_RESULT=1 \
+    out="$("$ROOT/target/release/nyash" --json-file "$json_path" 2>&1)"
+  printf '%s\n' "$out" | awk '/^(✅|ResultType|Result:)/{next} NF{last=$0} END{ if(last) print last }'
+  local rc=$?
+  rm -f "$json_path"
+  return $rc
+}
+
+info "Stage-B v1 compat: return literal"
+json_path=$(compile_stageb_v1 'box Main { static method main() { return 42; } }') || skip "Stage-B v1 compat compilation not available"
+out=$(run_gate_c "$json_path")
+if [ "$out" = "42" ]; then
+  pass "stageb_v1_return"
+else
+  printf 'Expected: 42\nActual:   %s\n' "$out" >&2
+  fail "stageb_v1_return"
+fi
+
+exit 0