Fix: Remove redundant signature generation in publishService

The rondevu.ts wrapper was generating its own message and signature
which were being ignored by the API layer (which generates its own).
This caused the old signature to be passed but not used.

Simplified by removing the redundant code and letting the API layer
handle all authentication.

🤖 Generated with Claude Code
https://claude.com/claude-code

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/rondevu.ts

@@ -176,21 +176,15 @@ export class Rondevu {
 
         const { serviceFqn, offers, ttl } = options
 
-        // Generate signature for service publication
-        const message = `publish:${this.username}:${serviceFqn}:${Date.now()}`
-        const signature = await RondevuAPI.signMessage(message, this.keypair.privateKey)
-
-        // Create service request
-        const serviceRequest: ServiceRequest = {
-            serviceFqn, // Must include @username
-            offers,
-            signature,
-            message,
-            ttl,
-        }
-
         // Publish to server (server will auto-claim username if needed)
-        const result = await this.getAPI().publishService(serviceRequest)
+        // Note: signature and message are generated by the API layer
+        const result = await this.getAPI().publishService({
+            serviceFqn,
+            offers,
+            ttl,
+            signature: '', // Not used, generated by API layer
+            message: '',   // Not used, generated by API layer
+        })
 
         // Mark username as claimed after successful publish
         this.usernameClaimed = true