Implement onboarding reset functionality and enhance backup features

- Added a new method to reset the onboarding state, allowing users to re-initiate the onboarding process.
- Integrated backup creation functionality, enabling users to create encrypted backups of their node identity.
- Updated API endpoints to handle onboarding reset and backup creation requests.
- Enhanced UI components to support the new onboarding reset and backup features, including error handling and user feedback.
- Introduced new dependencies for cryptographic operations and data encoding.

neode-ui/mock-backend.js

@@ -693,6 +693,12 @@ app.post('/rpc/v1', (req, res) => {
         return res.json({ result: userState.onboardingComplete })
       }
 
+      case 'auth.resetOnboarding': {
+        userState.onboardingComplete = false
+        console.log('[Auth] Onboarding reset')
+        return res.json({ result: true })
+      }
+
       case 'node.did': {
         const mockDid = 'did:key:z6MkpTHR8VNsBxYAAWHut2Geadd9jSwuBV8xRoAnwWsdvktH'
         const mockPubkey = 'a1b2c3d4e5f6789012345678901234567890abcdef1234567890abcdef123456'
@@ -705,6 +711,32 @@ app.post('/rpc/v1', (req, res) => {
         return res.json({ result: { nostr_pubkey: 'mock-nostr-pubkey-hex' } })
       }
 
+      case 'node.signChallenge': {
+        const { challenge } = params || {}
+        const mockSig = Buffer.from(`mock-sig-${challenge || 'challenge'}`).toString('hex')
+        return res.json({ result: { signature: mockSig } })
+      }
+
+      case 'node.createBackup': {
+        const { passphrase } = params || {}
+        if (!passphrase) {
+          return res.json({ error: { code: -32602, message: 'Missing passphrase' } })
+        }
+        const mockDid = 'did:key:z6MkpTHR8VNsBxYAAWHut2Geadd9jSwuBV8xRoAnwWsdvktH'
+        const mockPubkey = 'a1b2c3d4e5f6789012345678901234567890abcdef1234567890abcdef123456'
+        return res.json({
+          result: {
+            version: 1,
+            did: mockDid,
+            pubkey: mockPubkey,
+            kid: `${mockDid}#key-1`,
+            encrypted: true,
+            blob: Buffer.from(`mock-encrypted-backup-${passphrase}`).toString('base64'),
+            timestamp: new Date().toISOString(),
+          },
+        })
+      }
+
       case 'auth.login': {
         const { password } = params