fix(dashboard): use args[1] pattern for positional arg parsing in resolve.ts

Align parseDashboardPositionalArgs with the established codebase pattern
used in event/view, trace/view, trace/logs, and dashboard/create.

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

Author: betegon

src/commands/dashboard/resolve.ts

@@ -77,7 +77,7 @@ export function parseDashboardPositionalArgs(args: string[]): {
     };
   }
   return {
-    dashboardRef: args.at(-1) as string,
+    dashboardRef: args[1] as string,
     targetArg: args[0] as string,
   };
 }