Feature Request: Support OSC 133 Shell Integration

### Problem
When using fish shell (and other modern shells like zsh with certain plugins), WindTerm displays escape sequences like `]133;A;click_events=1\~` at the end of prompts. These are OSC 133 sequences that modern shells use for shell integration features.

### What are OSC 133 sequences?
OSC 133 (Operating System Command 133) sequences are control codes that shells send to terminals to mark:
- Prompt start/end
- Command start/end
- Command output boundaries
- Command execution status

### Current Behavior
```
user@host ~ ]133;A;click_events=1\~
```

### Expected Behavior
WindTerm should either:
1. **Support OSC 133** (preferred) - Parse and use these sequences to enable features like:
- Click to select/copy command output (excluding prompt)
- Jump between commands with keyboard shortcuts
- Visual indicators for command success/failure
- Smart scrolling to previous commands

2. **Silently ignore** - Strip these sequences to avoid visual clutter

### Terminals with OSC 133 Support
- iTerm2
- WezTerm
- Visual Studio Code terminal
- Windows Terminal
- Alacritty (with recent versions)

### References
- [OSC 133 Specification](https://gitlab.freedesktop.org/Per_Bothner/specifications/-/blob/master/proposals/semantic-prompts.md)

Reproduce the stray OSC 133 output using fish or zsh, then trace WindTerm's terminal escape-sequence handling to find where these sequences are displayed. Done means OSC 133 sequences are either parsed for shell-integration behavior or silently removed so they no longer appear in prompts.

Written by the indexing model from the issue text.