Move runtime details action prompt to the end

[rianjs]

Problem

In the interactive cr init LLM runtime details workflow, the Runtime detail action prompt appears before the user reviews or changes the runtime provider, auth mode, and adapter fields.

That makes the flow feel backwards: the user is asked whether to stage details before completing the details themselves.

Desired behavior

Move the Runtime detail action choice to the bottom of this workflow, after the runtime fields such as:

• LLM provider
• LLM auth mode
• LLM adapter

The user should make field selections first, then choose whether to stage the runtime details or go back without staging.

Acceptance criteria

• The runtime detail action prompt is rendered after the runtime configuration fields.
• Existing choices remain available: Stage these runtime details and Back without staging.
• Existing validation/staging behavior is unchanged.
• Tests cover the new prompt ordering.