fix(rpubs): fix shadow root double-attach and PDF generate route

- Guard attachShadow with existing check to prevent crash on reconnect
- Fix API path: /pubs/api/generate → /rpubs/api/generate (module ID is rpubs)
- The "Unexpected non-whitespace character" error was HTML 404 parsed as JSON

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

modules/rpubs/components/folk-pubs-editor.ts

@@ -98,7 +98,7 @@ export class FolkPubsEditor extends HTMLElement {
 	}
 
 	async connectedCallback() {
-		this.attachShadow({ mode: "open" });
+		if (!this.shadowRoot) this.attachShadow({ mode: "open" });
 		this._tour = new TourEngine(
 			this.shadowRoot!,
 			FolkPubsEditor.TOUR_STEPS,
@@ -598,7 +598,7 @@ export class FolkPubsEditor extends HTMLElement {
 			this.render();
 
 			try {
-				const res = await fetch(`/${this._spaceSlug}/pubs/api/generate`, {
+				const res = await fetch(`/${this._spaceSlug}/rpubs/api/generate`, {
 					method: "POST",
 					headers: { "Content-Type": "application/json" },
 					body: JSON.stringify({