fix: Enhanced duplicate response guidance for self-correction

[gdeyoung]

Summary

This PR addresses the ROOT CAUSE of duplicate message loops by providing the LLM with context and specific guidance to self-correct BEFORE the circuit breaker kicks in.

Problem

When the LLM gets stuck in a loop, it:

1. Doesn't know it's in a loop (no context)
2. Doesn't have specific guidance on alternatives

Solution

1. Add retry count context - Pass to warning message so LLM knows its loop status
2. Provide specific alternatives - 4 concrete approaches to break the loop:
   • If uncertain: Ask user for clarification
   • If stuck: Try different tool/approach
   • If blocked: Explain blocker and needs
   • If waiting: Report status instead of repeating
3. Track duplicates - Counter for context (resets on success)

Changes

File	Changes
	+6 lines (counter, increment, reset, pass retry_count)
	+14 lines (enhanced guidance with template)

How It Works

Relationship to PR #1265

• PR fix: Add duplicate response loop breaker to prevent infinite loops #1265 (Circuit Breaker): Safety net - breaks loop after 3 duplicates
• This PR (Enhanced Guidance): Root cause fix - helps LLM self-correct BEFORE circuit breaker

Both PRs work together for defense-in-depth:

1. First line of defense: Enhanced guidance (this PR)
2. Last line of defense: Circuit breaker (PR fix: Add duplicate response loop breaker to prevent infinite loops #1265)

Testing

• Warning now shows "attempt X/3" for context
• LLM receives specific alternatives instead of generic "do something else"
• Counter resets on successful iteration

Related Issues

Addresses root cause of #1056, #1000, #1187, #1011

Notes

This is a minimal, elegant fix that addresses the root cause without modifying core logic. The LLM now has the context and guidance it needs to break loops itself.