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/shared/json/mir_builder_min.hako

@@ -59,11 +59,11 @@ box MirJsonBuilderMin {
     if arr_text == null { return out }
     local s = "" + arr_text
     local i = 0
-    loop (i < s.size()) {
+    loop (i < s.length()) {
       local ch = s.substring(i, i+1)
       if ch >= "0" && ch <= "9" {
         local j = i
-        loop (j < s.size()) {
+        loop (j < s.length()) {
           local cj = s.substring(j, j+1)
           if !(cj >= "0" && cj <= "9") { break }
           j = j + 1
@@ -104,9 +104,9 @@ box MirJsonBuilderMin {
   start_block(id) {
     me.phase = 3
     me.first_inst = 1
-    local blk = map({ id: id, instructions: new ArrayBox() })
+    local blk = { id: id, instructions: new ArrayBox() }
     me.blocks.push(blk)
-    me.cur_block_index = me.blocks.size() - 1
+    me.cur_block_index = me.blocks.length() - 1
     local b = "{\"id\":" + me._int_to_str(id) + ",\"instructions\":["
     return me._append(b)
   }
@@ -399,7 +399,7 @@ box MirJsonBuilderMin {
 
   get_function_structure() {
     local blks = me.get_blocks_array()
-    return map({ name: me.fn_name, params: new ArrayBox(), blocks: blks })
+    return { name: me.fn_name, params: new ArrayBox(), blocks: blks }
   }
 
   emit_to_string() { return me.to_string() }
@@ -412,7 +412,7 @@ box MirJsonBuilderMin {
     local blks_size_str = "null"
     local blks_len = BoxHelpers.array_len(blks)
     if blks_len >= 0 { blks_size_str = me._int_to_str(blks_len) }
-    print("[DEBUG rebuild] fn_name=" + name + " blks.size()=" + blks_size_str)
+    print("[DEBUG rebuild] fn_name=" + name + " blks.length()=" + blks_size_str)
     local out = "{\"functions\":[{\"name\":" + me._quote(name) + ",\"params\":[],\"blocks\":["
     local n = blks_len
     print("[DEBUG rebuild] n=" + me._int_to_str(n))