fix: resolve TypeScript build errors for AuthenticatorTransport and bech32 types

- Cast transports to AuthenticatorTransport[] for StoredCredential compatibility
- Add template literal type assertion for bech32.decode npub parameter

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: vveerrgg

src/server/webauthn.ts

@@ -151,7 +151,7 @@ export class WebAuthnServer {
           counter: registrationInfo.counter,
           credentialBackedUp: registrationInfo.credentialBackedUp,
           credentialDeviceType: registrationInfo.credentialDeviceType,
-          transports: credential.response.transports as AuthenticatorTransportFuture[] | undefined,
+          transports: credential.response.transports as unknown as AuthenticatorTransport[] | undefined,
         };
 
         this.credentials.set(userId, [...userCreds, storedCredential]);

src/utils/index.ts

@@ -15,7 +15,7 @@ export function npubToHex(npub: string): string {
     }
     // Decode the full bech32 string directly — npub1... is already valid bech32
     // with 'npub' as the human-readable part and '1' as the separator
-    const decoded = bech32.decode(npub, 1500);
+    const decoded = bech32.decode(npub as `npub1${string}`, 1500);
     const pubkeyBytes = bech32.fromWords(decoded.words);
     return Buffer.from(pubkeyBytes).toString('hex');
   } catch (error) {