fix(qr): resolve scanner race condition and crashes

This commit addresses several issues related to the QR code scanner:

- Fixes a build failure by defining stable handlers (`handleRestoreClose`, `handleRestoreError`) for the QRScanner component in `App.tsx` using `useCallback`.
- Resolves a race condition that caused an `AbortError` when the scanner was initialized, particularly in React Strict Mode. This was fixed by ensuring all props passed to the scanner are stable.
- Implements more robust error handling within the `QRScanner` component to prevent crashes when `null` or `undefined` errors are caught.
- Updates documentation (`README.md`, `GEMINI.md`) to version 1.4.5.

GEMINI.md

@@ -2,7 +2,7 @@
 
 ## Project Overview
 
-**SeedPGP v1.4.4**: Client-side BIP39 mnemonic encryption webapp  
+**SeedPGP v1.4.5**: Client-side BIP39 mnemonic encryption webapp  
 **Stack**: Bun + Vite + React + TypeScript + OpenPGP.js + Tailwind CSS  
 **Deploy**: Cloudflare Pages (private repo: `seedpgp-web`)  
 **Live URL**: <https://seedpgp-web.pages.dev/>
@@ -300,13 +300,12 @@ await window.runSessionCryptoTest()
 
 ---
 
-## Current Version: v1.4.4
+## Current Version: v1.4.5
 
-**Recent Changes (v1.4.4):**
-- Enhanced security documentation with explicit threat model
-- Improved README with simple examples and best practices
-- Better air-gapped usage guidance for maximum security
-- Version bump with security audit improvements
+**Recent Changes (v1.4.5):**
+- Fixed QR Scanner bugs related to camera initialization and race conditions.
+- Improved error handling in the scanner to prevent crashes and provide better feedback.
+- Stabilized component props to prevent unnecessary re-renders and fix `AbortError`.
 
 **Known Limitations (Critical):**
 1. **Browser extensions** can read DOM, memory, keystrokes - use dedicated browser