⚡ Bolt: Cache compiled Regex instances to speed up Scanner creation

[tachyon-beep]

💡 What: Added std::sync::OnceLock caching to Scanner::new() in crates/clarion-scanner/src/patterns.rs. We added #[derive(Clone)] to Scanner and CompiledPattern to clone the cached references.

🎯 Why: Regex::new is computationally expensive because it compiles regular expressions into DFA/NFA representations. Scanner::new() used to eagerly compile the default secrets scanning patterns every time it was called. This causes significant overhead whenever the CLI or server creates a new scanner instance.

📊 Impact: Redundant Regex compilation is completely eliminated. Cloning a cached Regex or RegexSet instance only bumps an Arc atomic reference count internally, making subsequent creations virtually instantaneous.

🔬 Measurement: To verify the improvement, compare Scanner::new() instantiation time before and after. cargo check and cargo test --workspace pass flawlessly.

---

PR created automatically by Jules for task 13339495316346839477 started by @tachyon-beep

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.