nip07: return a VerifiedEvent

nip07.ts

@@ -1,8 +1,8 @@
-import { EventTemplate, NostrEvent } from './core.ts'
+import { EventTemplate, VerifiedEvent } from './core.ts'
 
 export interface WindowNostr {
   getPublicKey(): Promise<string>
-  signEvent(event: EventTemplate): Promise<NostrEvent>
+  signEvent(event: EventTemplate): Promise<VerifiedEvent>
   nip04?: {
     encrypt(pubkey: string, plaintext: string): Promise<string>
     decrypt(pubkey: string, ciphertext: string): Promise<string>