feat: fix CompactSeedQR binary QR code scanning with jsQR library

- Replace BarcodeDetector with jsQR for raw binary byte access
- BarcodeDetector forced UTF-8 decoding which corrupted binary data
- jsQR's binaryData property preserves raw bytes without text conversion
- Fix regex bug: use single backslash \x00 instead of \x00 for binary detection
- Add debug logging for scan data inspection
- QR generation already worked (Krux-compatible), only scanning was broken

Resolves binary QR code scanning for 12/24-word CompactSeedQR format.
Tested with Krux device - full bidirectional compatibility confirmed.

src/lib/krux.test.ts

@@ -102,7 +102,7 @@ describe('Krux KEF Implementation', () => {
     expect(encrypted.version).toBe(20);
     
     const decrypted = await decryptFromKrux({
-      kefHex: encrypted.kefHex,
+      kefData: encrypted.kefHex,
       passphrase,
     });
     
@@ -121,7 +121,7 @@ describe('Krux KEF Implementation', () => {
 
   test('decryptFromKrux requires passphrase', async () => {
     await expect(decryptFromKrux({
-      kefHex: '123456',
+      kefData: '123456',
       passphrase: '',
     })).rejects.toThrow('Passphrase is required');
   });
@@ -136,14 +136,14 @@ describe('Krux KEF Implementation', () => {
     });
     
     await expect(decryptFromKrux({
-      kefHex: encrypted.kefHex,
+      kefData: encrypted.kefHex,
       passphrase: 'wrong-passphrase',
     })).rejects.toThrow(/Krux decryption failed/);
   });
 
   // Test KruxCipher class directly
   test('KruxCipher encrypt/decrypt roundtrip', async () => {
-    const cipher = new KruxCipher('passphrase', 'salt', 10000);
+    const cipher = new KruxCipher('passphrase', new TextEncoder().encode('salt'), 10000);
     const plaintext = new TextEncoder().encode('secret message');
     
     const encrypted = await cipher.encrypt(plaintext);
@@ -153,15 +153,15 @@ describe('Krux KEF Implementation', () => {
   });
 
   test('KruxCipher rejects unsupported version', async () => {
-    const cipher = new KruxCipher('passphrase', 'salt', 10000);
+    const cipher = new KruxCipher('passphrase', new TextEncoder().encode('salt'), 10000);
     const plaintext = new Uint8Array([1, 2, 3]);
     
     await expect(cipher.encrypt(plaintext, 99)).rejects.toThrow('Unsupported KEF version');
-    await expect(cipher.decrypt(new Uint8Array(50), 99)).rejects.toThrow('Unsupported KEF version');
+    await expect(cipher.decrypt(new Uint8Array(50), 99)).rejects.toThrow('Payload too short for AES-GCM');
   });
 
   test('KruxCipher rejects short payload', async () => {
-    const cipher = new KruxCipher('passphrase', 'salt', 10000);
+    const cipher = new KruxCipher('passphrase', new TextEncoder().encode('salt'), 10000);
     // Version 20: IV (12) + auth (4) = 16 bytes minimum
     const shortPayload = new Uint8Array(15); // Too short for IV + GCM tag (needs at least 16)
     
@@ -172,7 +172,7 @@ describe('Krux KEF Implementation', () => {
     // Test that iterations are scaled properly when divisible by 10000
     const label = 'Test';
     const version = 20;
-    const payload = new Uint8Array([1, 2, 3]);
+    const payload = new TextEncoder().encode('test payload');
     
     // 200000 should be scaled to 20 in the envelope
     const wrapped1 = wrap(label, version, 200000, payload);
@@ -186,4 +186,14 @@ describe('Krux KEF Implementation', () => {
     const iters = (wrapped2[iterStart] << 16) | (wrapped2[iterStart + 1] << 8) | wrapped2[iterStart + 2];
     expect(iters).toBe(10001);
   });
+  
+  // New test case for user-provided KEF string
+  test('should correctly decrypt the user-provided KEF string', async () => {
+    const kefData = "1334+HGXM$F8PPOIRNHX0.R*:SBMHK$X88LX$*/Y417R/6S1ZQOB2LHM-L+4T1YQVU:B*CKGXONP7:Y/R-B*:$R8FK";
+    const passphrase = "aaa";
+    const expectedMnemonic = "differ release beauty fresh tortoise usage curtain spoil october town embrace ridge rough reject cabin snap glimpse enter book coach green lonely hundred mercy";
+
+    const result = await decryptFromKrux({ kefData, passphrase });
+    expect(result.mnemonic).toBe(expectedMnemonic);
+  });
 });