docs: Add documentation for HITL history preservation fix

[kausmeows]

Summary

This PR adds comprehensive documentation for the history preservation fix in Human-in-the-Loop (HITL) scenarios, as implemented in agno-agi/agno#6888.

Documentation Added

1. Updated Main User Confirmation Page (hitl/user-confirmation.mdx)

   • Added a tip about history preservation when using continue_run()
   • Added a new "History Preservation" section with detailed example

2. Created New Usage Example (hitl/usage/confirmation-required-with-history.mdx)

   • Comprehensive example demonstrating the fix
   • Shows how user introductions and context are preserved
   • Includes sync, async, and streaming code examples

3. Updated History Overview (history/agent/overview.mdx)

   • Added "History Preservation in Human-in-the-Loop" section
   • Explains automatic history preservation in HITL scenarios

4. Created Troubleshooting Guide (hitl/troubleshooting.mdx)

   • New troubleshooting page for HITL features
   • First section addresses the "Conversation History Not Preserved" issue
   • Notes that version 0.34.0 includes this fix

Related PR

• Source PR: fix: resolved continue_run, missing history messages issue agno#6888

The documentation explains how the fix ensures conversation history is maintained when continuing paused runs, preserving context like user introductions across tool confirmations.

[kausmeows]

not needed