feat: interrupt with prompt

[lucamotz]

Issue for this PR

Closes #32157

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Adds one-step interrupt-and-steer actions to the TUI and app. They stop the active response before sending the correction through the existing prompt path.

How did you verify your code works?

• Typechecks and focused prompt/composer tests
• Core interrupt-continuation tests
• V2 build and live TUI stream abort
• App E2E asserting interrupt-before-prompt ordering

Screenshots / recordings

Before	After

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found one potentially related PR:

Related PR:

• fix(session): answer queued prompts after a stopped turn (PR fix(session): answer queued prompts after a stopped turn #48339)
  • This PR is about handling prompts after stopping a turn, which is closely related to the interrupt and prompt steering logic in PR feat: interrupt with prompt #48359

The other results that mention "interrupt" (like #32425 about interrupting running subagents and #46721 about typed job outcomes for stops) are related to the broader interrupt infrastructure but not direct duplicates of the current PR's specific functionality of interrupting with a prompt action.