🛡️ Sentinel: [HIGH] Validate webhook URLs in CSV import

[Pmaster-dev]

🚨 Severity: HIGH
💡 Vulnerability: Webhook CSV import in CSVImportService.ts did not validate URL format or scheme before storing webhook records.
🎯 Impact: Attackers could import webhooks with malicious schemes (e.g., javascript:, file:) or malformed URLs leading to SSRF or unexpected behavior.
🔧 Fix: Enforced URL parsing and restricted webhook URLs strictly to http: and https: protocols during CSV import.
✅ Verification: Added unit tests in server/services/CSVImportService.test.ts to verify valid HTTP(S) URLs are accepted while invalid protocols and malformed strings are rejected.

---

PR created automatically by Jules for task 14312009642451468574 started by @Pmaster-dev

[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.