🛡️ Sentinel: [HIGH] Fix XSS in WebView

[TargetMisser]

🚨 Severity: HIGH
💡 Vulnerability: The application was vulnerable to Cross-Site Scripting (XSS) via WebView integration. Base64 strings representing user-uploaded images and documents were being directly injected via injectJavaScript or raw string interpolation into HTML template contexts.
🎯 Impact: While standard Base64 parsing limits character sets, direct code injection patterns and raw HTML string interpolations violate security boundaries, risking code execution if an attacker somehow bypasses the parser or manipulates inputs to break string enclosures within the JS execution context of the WebView.
🔧 Fix:

1. Replaced injectJavaScript inside HomeScreen and ShiftScreen with the secure postMessage architecture.
2. Updated the WebView HTML content to explicitly handle messages via robust event listeners attached to both window and document to avoid unverified execution.
3. Fixed CalendarScreen to implement a deterministic READY handshake, preventing race conditions ensuring the payload is only passed when the WebView DOM and internal modules are fully mounted and ready to process postMessage data.
   ✅ Verification: Verified via TypeScript static analysis (npm run typecheck).

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PR created automatically by Jules for task 17356413257623056766 started by @TargetMisser

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Project	Deployment	Actions	Updated (UTC)
flight-work-app	Ready	Preview, Comment, Open in v0	Apr 24, 2026 1:23am