Add workspace-owner credit nudge flow to the CLI.

Expose workspace-owner account metadata and an app-server nudge endpoint so users who run out of credits can inspect usage and notify their workspace owner directly from the TUI.

Made-with: Cursor

codex-rs/app-server-protocol/schema/json/ServerNotification.json

@@ -51,6 +51,12 @@
             }
           ]
         },
+        "isWorkspaceOwner": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "planType": {
           "anyOf": [
             {