Add browsing history

[lambdalisue]

Summary

Track viewed files and provide quick access to previously opened files through history navigation.

Motivation

When working across multiple files, users frequently need to return to previously viewed files. Browser-like back/forward navigation and a history list would significantly improve navigation efficiency.

Proposed Behavior

• Back / Forward: Browser-like navigation with keyboard shortcuts
• History list: Display recently opened files for quick selection
• Persistence: Retain history across app restarts (via state.json or dedicated file)
• Per-window: Each window maintains its own independent history stack

Notes

• Can build on top of the existing HistoryManager
• Need to consider interaction with tab switching