refactor(playground): Simplify execution API by removing graphUrl param

Removes the graphUrl parameter from execution flow since it's now fetched
directly from the database using agentId. This simplifies the API and
prevents potential URL manipulation.

- Remove graphUrl parameter from ExecutionProvider interface
- Update execute function signature in page component
- Remove unnecessary graphUrl passing in execution context

app/(playground)/p/[agentId]/canary/contexts/execution.tsx

@@ -20,7 +20,6 @@ interface ExecutionProviderProps {
 	children: ReactNode;
 	executeAction: (
 		artifactId: ArtifactId,
-		graphUrl: string,
 		nodeId: NodeId,
 	) => Promise<StreamableValue<TextArtifactObject, unknown>>;
 }
@@ -56,9 +55,9 @@ export function ExecutionProvider({
 				},
 			});
 			setTab("Result");
-			const latestGraphUrl = await flush();
+			await flush();
 			try {
-				const stream = await executeAction(artifactId, latestGraphUrl, nodeId);
+				const stream = await executeAction(artifactId, nodeId);
 
 				let textArtifactObject: TextArtifactObject = {
 					type: "text",

app/(playground)/p/[agentId]/canary/page.tsx

@@ -87,11 +87,7 @@ export default async function Page({
 		return agentName;
 	}
 
-	async function execute(
-		artifactId: ArtifactId,
-		graphUrl: string,
-		nodeId: NodeId,
-	) {
+	async function execute(artifactId: ArtifactId, nodeId: NodeId) {
 		"use server";
 		return await action(artifactId, agentId, nodeId);
 	}