[Bug] TaskStop reports success when the stop RPC fails

[alexei-led]

Summary

TaskStop reports success and marks a subagent task as completed when the stop RPC fails.

Evidence

stopSubagent() catches every RPC error and returns a resolved promise:

• src/index.ts:197-200

TaskStop then updates the task to completed and returns a success message:

• src/index.ts:965-972

Reproduction

1. Start a task with TaskExecute.
2. Make the subagents:rpc:stop reply return an error or timeout.
3. Call TaskStop for the task.
4. Read the task with TaskGet or TaskList.

Expected behavior

The tool returns an error when the stop RPC fails. The task stays in_progress, or uses a clear stopping state.

Actual behavior

The tool returns Task ... stopped successfully. The task has status completed, although the subagent can still run.

Impact

The task list reports a false result. A dependent task can start while the stopped subagent still runs.

Requested change

• Do not catch and ignore stop RPC errors.
• Do not mark the task as completed after a failed stop request.
• Keep the existing stopped-event handler as the source for final completion.
• Add a regression test for an RPC error and a timeout.