refactor(agents): remove dead code and fix duplicate ID bug
Remove dead/redundant code identified in comprehensive code review:
- Remove unused _agents_dir() function from agents.py
- Remove misleading asyncio comment
- Remove dead CSS rules (.toggle-btn, .selection-status)
- Remove obsolete code comments
- Delete non-existent agentInput element reference
Fix critical duplicate ID bug:
- Rename promptEditor to itemContentEditor in #itemModal
- Update all 7 references to use correct element ID
- Prevents getElementById collision between modals
Improve code quality:
- Consolidate duplicate .prompt-content CSS into distinct classes
- Replace window globals with module-level variables
- Add clear comments to disambiguate similar CSS classes
Impact: -55 lines, fixed 1 critical bug, improved maintainability
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Co-Authored-By: Claude <noreply@anthropic.com>