Disable stream mode for manual prompts and flush output directly to stdout

[jihchi]

Fixes an issue where running muxclaw dispatch with a manual prompt and stream: true in the config would fail to print output to the terminal.

• Explicitly sets stream = false and stdout: 'inherit' when a prompt is provided directly on the CLI without an --id.
• Prevents errors related to trying to read an unpiped stdout.
• Updated tests to cover this scenario.