refactor: Convert conversationHandlers to async/await syntax

[ron-42]

Description

Refactors frontend/src/conversation/conversationHandlers.ts from legacy .then() chaining to modern async/await syntax for improved code maintainability and readability.

Fixes #2070

Changes Made

Refactored Functions (7 total):

• ✅ handleFetchAnswer - Main answer fetching handler
• ✅ handleFetchAnswerSteaming - Streaming response handler
• ✅ handleSearch - Document search handler
• ✅ handleSearchViaApiKey - API key-based search handler
• ✅ handleSendFeedback - User feedback submission handler
• ✅ handleFetchSharedAnswerStreaming - Shared conversation streaming handler
• ✅ handleFetchSharedAnswer - Shared conversation answer handler

Key Improvements:

• 🔄 Replaced .then() chains with async/await for linear, readable code flow
• ✅ Improved error handling using try/catch blocks instead of .catch()
• 🎯 Maintained exact same functionality and return types (no breaking changes)
• 📝 Added missing toolCalls type to handleFetchSharedAnswer return type
• 🧹 Cleaner error propagation with direct throw statements

Testing

• ✅ TypeScript compilation passes with no errors
• ✅ ESLint validation passes
• ✅ Manual testing completed:
  • Basic Q&A functionality works correctly
  • Streaming responses render properly
  • Document search operates as expected
  • Feedback submission successful
  • Shared conversations with API keys functional
  • Multiple document selection works
  • File attachments handled correctly
• ✅ No breaking changes - all existing functionality preserved

Code Quality

• Follows modern JavaScript/TypeScript best practices
• Maintains consistency with the rest of the codebase
• No changes to function signatures or public APIs
• Backward compatible with all existing code

Type of Change

• Refactoring (no functional changes, code improvement)
• Code quality improvement

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have tested my changes locally
• My changes generate no new warnings or errors
• No breaking changes introduced

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Project	Deployment	Preview	Comments	Updated (UTC)
oss-docsgpt	Ready	Preview	Comment	Oct 17, 2025 3:30pm

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.27%. Comparing base (498e2b7) to head (f117527).
⚠️ Report is 91 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2072      +/-   ##
==========================================
+ Coverage   34.67%   39.27%   +4.59%     
==========================================
  Files         131      135       +4     
  Lines        8703     9296     +593     
==========================================
+ Hits         3018     3651     +633     
+ Misses       5685     5645      -40     

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