refactor(build): 构建产物目录去掉 _mlir 后缀（temp/output）

TempDir/OutputDir 回归 {BuildDir}/temp 与 {BuildDir}/output，与 TPC 及项目脚本预期一致；mlir_dir_suffix() 仅保留给 includes 二进制缓存（其布局为 sha1 子目录，与 TPC 的扁平 obj 缓存不同，合并会混淆）。

App/lib/Phase/Phase2/__init__.vp

@@ -1433,7 +1433,7 @@ def RunMultiFileProject(mb: memhub.MemBuddy*, source_dir: str, temp_dir: str, ou
             string.strcpy(final_obj_paths, main_obj_path)
             fop_pos = mlen
 
-        # Merge the App non-main modules' .obj (obj_paths, space-separated) compiled by Phase B/B+.
+        # Merge the App non-main modules' .obj (obj_paths, space-separated) compiled by Phase B/B+.
         # final_obj_paths must include main_obj + reachable includes + App deps, else linking hits undefined symbols.
         if obj_pos > 0:
             if fop_pos + obj_pos + 1 < OBJ_PATHS_SIZE + 512: