ROO-411: Simplify no assistant message retry behavior

[roomote]

Simplifies the 'no assistant message' error path to match the simpler 'no tools used' pattern, improving UX for models like Grok that may repeatedly return reasoning-only responses.

Summary

This PR addresses ROO-411 by simplifying the complex retry logic for when models return only reasoning/thinking blocks without text or tool calls.

Changes

1. Added format helper in

   • Provides consistent error messaging and instructions similar to

2. Simplified retry logic in (lines 3522-3621)

   • Reduced from ~100 lines to ~15 lines
   • Matches the 'no tools used' pattern:
     • Increment counter
     • Show error only after 2 consecutive failures (grace retry on first)
     • Increment on second failure
     • Push prompt to
     • Let loop continue naturally
   • Removed complex auto-approval/manual retry branches that could cause poor UX or infinite loops

Benefits

• Better UX: Simpler, more predictable retry behavior
• Prevents infinite loops: No complex backoff/approval checks that could hang with models like Grok
• Consistency: Both 'no tools' and 'no assistant message' errors now behave the same way
• Maintainability: ~85 fewer lines of complex conditional logic

Testing

• Type checking: ✓ Passed
• Linting: ✓ Passed

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View task on Roo Code Cloud

[roomote]

Rooviewer   See task on Roo Cloud

All issues have been addressed. The fix correctly pushes the noAssistantMessage prompt to the stack and uses continue to retry, matching the "no tools used" pattern.

• noAssistantMessage prompt is never sent to the model due to control flow issue (Task.ts:3538-3543) - Resolved in ab42a9c

Previous reviews

• 088a90b: Review #1

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote]

Fixaroo   See task on Roo Cloud

Fixed the control flow issue. The noAssistantMessage block now pushes to stack and continues the loop instead of falling through to return false.

_{View commit | Revert commit}

[daniel-lxs]

We need this logic if there's no assistant message to prevent the conversation to fall in an invalid state.