fix(mir): PHI検証panic修正 - update_cfg()を検証前に呼び出し

A案実装: debug_verify_phi_inputs呼び出し前にCFG predecessorを更新

修正箇所（7箇所）:
- src/mir/builder/phi.rs:50, 73, 132, 143
- src/mir/builder/ops.rs:273, 328, 351

根本原因:
- Branch/Jump命令でsuccessorは即座に更新
- predecessorはupdate_cfg()で遅延再構築
- PHI検証が先に実行されてpredecessor未更新でpanic

解決策:
- 各debug_verify_phi_inputs呼び出し前に
  if let Some(func) = self.current_function.as_mut() {
      func.update_cfg();
  }
  を挿入してCFGを同期

影響: if/else文、論理演算子(&&/||)のPHI生成が正常動作

lang/src/llvm_ir/instructions/branch.hako

@@ -36,7 +36,7 @@ static box LLVMBranchInstructionBox {
   batch_branch(branch_list) {
     local results = []
     local i = 0
-    while i < branch_list.size() {
+    while i < branch_list.length() {
       local branch = branch_list[i]
       local json = me.lower_branch(branch.cond, branch.then_block, branch.else_block)
       results.push(json)

lang/src/llvm_ir/instructions/compare.hako

@@ -60,7 +60,7 @@ static box LLVMCompareInstructionBox {
   batch_compare(compare_list) {
     local results = []
     local i = 0
-    while i < compare_list.size() {
+    while i < compare_list.length() {
       local cmp = compare_list[i]
       local json = me.lower_compare(cmp.op, cmp.lhs, cmp.rhs, cmp.dst)
       results.push(json)

lang/src/llvm_ir/instructions/copy.hako

@@ -40,7 +40,7 @@ static box LLVMCopyInstructionBox {
   batch_copy(copy_list) {
     local results = []
     local i = 0
-    while i < copy_list.size() {
+    while i < copy_list.length() {
       local copy = copy_list[i]
       local json = me.lower_copy(copy.dst, copy.src)
       results.push(json)

lang/src/llvm_ir/instructions/jump.hako

@@ -45,7 +45,7 @@ static box LLVMJumpInstructionBox {
   batch_jump(jump_list) {
     local results = []
     local i = 0
-    while i < jump_list.size() {
+    while i < jump_list.length() {
       local jump = jump_list[i]
       local json = me.lower_jump(jump.target)
       results.push(json)