perf(compile): 批次加权分桶消除长尾 + 共享符号表去重复序列化 + typedef 收集走 AST 缓存

- Phase2 批次切分：原按文件数均分（batch_size=ceil(N/n)），大文件集中批次拖长尾、worker 空等；改为按源文件大小 LPT 贪心分桶，各批次总成本均匀（任务颗粒度不均匀）
- 共享符号表序列化：shared_data 同时含 symbol_table 对象与 symbol_table_bytes 双重序列化（_shared_sym.json 4.65MB 近半冗余）；统一为仅传 symbol_table_bytes，worker/批次端从字节反序列化（includes 与 App 两阶段同步修改）
- Phase1 _collect_typedef_map / _process_file_pyi：直读+ast.parse 改为 parse_python_file mtime AST 缓存，Phase1 内重复收集与 Phase2 主进程解析共享同一缓存

lib/Projectrans/Phase1Generator.py

@@ -357,9 +357,9 @@ class Phase1Generator:
                 continue
             pyi_path: str = os.path.join(self.temp_dir, fname)
             try:
-                with open(pyi_path, 'r', encoding='utf-8') as f:
-                    content: str = f.read()
-                tree: ast.Module = ast.parse(content)
+                content, tree = parse_python_file(pyi_path)
+                if tree is None:
+                    continue
                 for node in ast.iter_child_nodes(tree):
                     if isinstance(node, ast.AnnAssign) and isinstance(node.target, ast.Name):
                         var_name: str = node.target.id
@@ -676,9 +676,9 @@ class Phase1Generator:
                 continue
             pyi_path: str = os.path.join(self.temp_dir, fname)
             try:
-                with open(pyi_path, 'r', encoding='utf-8') as f:
-                    content: str = f.read()
-                tree: ast.Module = ast.parse(content)
+                content, tree = parse_python_file(pyi_path)
+                if tree is None:
+                    continue
                 for node in ast.iter_child_nodes(tree):
                     if isinstance(node, ast.ClassDef):
                         is_enum: bool = False