orch: require explicit dispatch execution mode

docs/tests/orch/dispatch/dispatch-creates-strict-worktree.md

@@ -2,7 +2,7 @@
 
 ## 用例意义
 
-验证显式 `--strict-worktree` dispatch 会创建隔离 worktree，并把 workspace 元数据持久化到 attempt 与任务 payload 中。
+验证显式 `--execution-mode code` dispatch 会创建隔离 worktree，并把 workspace 元数据持久化到 attempt 与任务 payload 中。
 
 ## 前置条件
 
@@ -15,7 +15,7 @@
 ```bash
 orch --db TMPDIR/coord.db --json run init --run run_blog_worktree_001 --goal "Validate strict worktree dispatch"
 orch --db TMPDIR/coord.db --json task add --run run_blog_worktree_001 --task T1 --title "Implement backend" --default-to worker-a
-orch --db TMPDIR/coord.db --json dispatch --run run_blog_worktree_001 --task T1 --repo-path TMPDIR/repo --workspace-root .orch/worktrees --strict-worktree --body "Implement inside isolated worktree."
+orch --db TMPDIR/coord.db --json dispatch --run run_blog_worktree_001 --task T1 --execution-mode code --repo-path TMPDIR/repo --workspace-root .orch/worktrees --body "Implement inside isolated worktree."
 ```
 
 ## 预期输出
@@ -26,11 +26,12 @@ orch --db TMPDIR/coord.db --json dispatch --run run_blog_worktree_001 --task T1
 - `data.attempt.branch_name == "orch/run-blog-worktree-001/T1/attempt-1"`
 - 返回非空 `data.attempt.worktree_path`
 - `data.attempt.workspace_status == "created"`
+- `data.message.payload_json.execution_mode == "code"`
 - `data.message.payload_json.worktree_path` 与 attempt 中的路径一致
 
 ## 断言结论
 
-- strict worktree dispatch 会创建真正的隔离工作目录，而不是只记录一组字符串元数据
+- code-mode dispatch 会创建真正的隔离工作目录，而不是只记录一组字符串元数据
 - worker 读取任务 payload 时可以拿到同一份 worktree 路径
 
 ## 补充约束