orch: require explicit dispatch execution mode

skills/orch/references/leader-dispatch-and-launch-checklist.md

@@ -14,7 +14,7 @@ Keep `orch` as the control plane and use a leader-side bridge to launch a worker
 4. save the dispatch response:
 
 ```bash
-./assets/orch --db ./coord.db --json dispatch --run RUN_ID --task TASK_ID > TMPDIR/dispatch.json
+./assets/orch --db ./coord.db --json dispatch --run RUN_ID --task TASK_ID --execution-mode analysis > TMPDIR/dispatch.json
 ```
 
 5. render a standardized worker brief:

skills/orch/references/worker-brief-template.md

@@ -39,3 +39,4 @@ Rules:
 - The template is intentionally worker-only. Leader control stays with `orch`.
 - The generated brief should be passed into a spawned worker sub-agent together with `skills/inbox/`.
 - Keep the main-thread launch parameters in the leader workflow, not in the worker brief.
+- `execution_mode` is part of the explicit dispatch contract and should come from the saved dispatch payload, not from local heuristics.