v0.7.0 - Search filters + real-world stats

✨ Features

• filters: Add grep / rg / ripgrep filter — group matches by file, configurable context
• filters: Add find / fd / fdfind filter — group results by directory, compact listings
• filters: Add env / printenv filter — hide system vars, mask *_KEY / *_SECRET / *_TOKEN, format PATH

📊 Real-World Stats

Updated README with actual wtk gain data:

• 924 commands tracked over 30 days
• 8.6M tokens saved (95.3% efficiency)
• 9.0M input tokens filtered → 420.6K output tokens
• Recursive find scans = top savers (60K–6.4M tokens per call)

📦 Install

```powershell
irm https://raw.githubusercontent.com/Lukreitor/wtk/master/install.ps1 | iex
```

Full Changelog: v0.6.1...v0.7.0