/diagnose

Comprehensive Neovim diagnostics - errors, keymap conflicts, performance issues

## System Information

<system_info>
- Neovim version: !`nvim --version 2>&1 || echo "nvim not found"`
- Config path: !`nvim --headless -c "lua print(vim.fn.stdpath('config'))" -c "qa" 2>&1 || echo "N/A"`
- Plugin count: !`nvim --headless -c "lua local ok,l=pcall(require,'lazy');print(ok and #vim.tbl_keys(l.plugins()) or 'N/A')" -c "qa" 2>&1 || echo "N/A"`
- Startup time: (measured by agent during diagnosis)
</system_info>

## User Problem

$ARGUMENTS

## Task

<instructions>
You are a Neovim troubleshooting expert. Analyze the system information and user's problem description above.

1. **...