Add search, word wrap, and log level filters to log viewer

Features added:
- Search input with real-time filtering and match highlighting
- Clear search button and match count display
- Log level filter toggles (Error, Warn, Info, Debug)
- Word wrap toggle for long log lines
- Keyboard shortcuts: Ctrl/Cmd+F to focus search, Esc to clear/close

UI improvements:
- New toolbar between header and status bar
- Filter badges with level-appropriate colors
- Responsive layout for mobile devices
- Shows visible/total line count when filtered

Author: anneschuth