feat(blender): add Seed Blender feature

Implements a new 'Seed Blender' feature that allows users to securely combine multiple BIP39 mnemonics and enhance them with dice roll entropy.

- Adds a new 'Seed Blender' tab to the main UI.
- Implements a multi-step workflow for inputting mnemonics (manual/QR) and dice rolls.
- Provides live validation and previews for blended seeds and dice-only entropy.
- Includes statistical analysis of dice rolls (chi-square, distribution) and pattern detection for quality assessment.
- The core logic is a 1-to-1 port of the reference Python implementation, using the Web Crypto API for browser compatibility and Node.js for testing.
- A full suite of unit tests ported from the reference implementation ensures correctness and deterministic outputs.

src/App.tsx

@@ -22,6 +22,7 @@ import Header from './components/Header';
 import { StorageDetails } from './components/StorageDetails';
 import { ClipboardDetails } from './components/ClipboardDetails';
 import Footer from './components/Footer';
+import { SeedBlender } from './components/SeedBlender';
 
 console.log("OpenPGP.js version:", openpgp.config.versionString);
 
@@ -39,11 +40,12 @@ interface ClipboardEvent {
 }
 
 function App() {
-  const [activeTab, setActiveTab] = useState<'backup' | 'restore'>('backup');
+  const [activeTab, setActiveTab] = useState<'backup' | 'restore' | 'seedblender'>('backup');
   const [mnemonic, setMnemonic] = useState('');
   const [backupMessagePassword, setBackupMessagePassword] = useState('');
   const [restoreMessagePassword, setRestoreMessagePassword] = useState('');
 
+
   const [publicKeyInput, setPublicKeyInput] = useState('');
   const [privateKeyInput, setPrivateKeyInput] = useState('');
   const [privateKeyPassphrase, setPrivateKeyPassphrase] = useState('');
@@ -418,7 +420,7 @@ function App() {
                        readOnly={isReadOnly}
                      />
                    </>
-                 ) : (
+                 ) : activeTab === 'restore' ? (
                    <>
                      <div className="flex gap-2">
                        <button
@@ -475,6 +477,8 @@ function App() {
                        </div>
                      )}
                    </>
+                 ) : (
+                    <SeedBlender />
                  )}
                </div>