Phase 21.7 normalization: optimization pre-work + bench harness expansion

- Add opt-in optimizations (defaults OFF)
  - Ret purity verifier: NYASH_VERIFY_RET_PURITY=1
  - strlen FAST enhancement for const handles
  - FAST_INT gate for same-BB SSA optimization
  - length cache for string literals in llvmlite
- Expand bench harness (tools/perf/microbench.sh)
  - Add branch/call/stringchain/arraymap/chip8/kilo cases
  - Auto-calculate ratio vs C reference
  - Document in benchmarks/README.md
- Compiler health improvements
  - Unify PHI insertion to insert_phi_at_head()
  - Add NYASH_LLVM_SKIP_BUILD=1 for build reuse
- Runtime & safety enhancements
  - Clarify Rust/Hako ownership boundaries
  - Strengthen receiver localization (LocalSSA/pin/after-PHIs)
  - Stop excessive PluginInvoke→BoxCall rewrites
- Update CURRENT_TASK.md, docs, and canaries

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tools/dev/phase217_methodize_canary.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/../.." && pwd)
+cd "$ROOT"
+
+TMP_SRC=$(mktemp --suffix .hako)
+cat >"$TMP_SRC" <<'HAKO'
+static box Main {
+  method add(a,b){ return a + b }
+  method main(){ return add(2,3) }
+}
+HAKO
+
+TMP_JSON=$(mktemp --suffix .json)
+
+# Emit MIR(JSON) with defs + call resolution + methodize (dev)
+HAKO_SELFHOST_BUILDER_FIRST=1 \
+HAKO_STAGEB_FUNC_SCAN=1 \
+HAKO_MIR_BUILDER_FUNCS=1 \
+HAKO_MIR_BUILDER_CALL_RESOLVE=1 \
+HAKO_MIR_BUILDER_METHODIZE=1 \
+NYASH_USE_NY_COMPILER=0 HAKO_DISABLE_NY_COMPILER=1 \
+NYASH_PARSER_STAGE3=1 HAKO_PARSER_STAGE3=1 NYASH_PARSER_ALLOW_SEMICOLON=1 \
+NYASH_ENABLE_USING=1 HAKO_ENABLE_USING=1 \
+  bash "$ROOT/tools/hakorune_emit_mir.sh" "$TMP_SRC" "$TMP_JSON" >/dev/null
+
+# Observability: prefer mir_call(Method), but tolerate delegate(Global) during bring-up
+if ! rg -q '"op"\s*:\s*"mir_call"' "$TMP_JSON" || ! rg -q '"callee"\s*:\s*\{[^}]*"type"\s*:\s*"Method"' "$TMP_JSON"; then
+  echo "[NOTE] methodize: mir_call(Method) not observed (delegate Global path likely). Proceeding with VM check." >&2
+  cp "$TMP_JSON" /tmp/phase217_methodize_last.json || true
+fi
+
+# Execute semantics via standard .hako compile path（JSON実行はv1検討中）
+BIN=${NY_BIN:-${NY_BIN:-$ROOT/target/release/hakorune}}
+set +e
+"$BIN" --backend vm "$TMP_SRC" >/dev/null 2>&1; rc=$?
+set -e
+if [[ "$rc" == "5" ]]; then
+  echo "[PASS] phase217_methodize (compile-run rc=5)"
+else
+  echo "[FAIL] phase217_methodize — compile-run rc=$rc" >&2
+  exit 1
+fi
+
+rm -f "$TMP_SRC" "$TMP_JSON" 2>/dev/null || true
+exit 0