Release v2.19.0

What's Changed

• Add OAuth Debugger e2e smoke by @ignaciojimenezr in #2878
• workos stuff by @ignaciojimenezr in #2867
• Show seat deltas in credit activity by @ignaciojimenezr in #2491
• Persist error toasts until dismissed by @ignaciojimenezr in #2877
• fix(xaa): clean up debugger UI and auto-recover stale local session token by @Vu-John in #2880
• Fix XAA Debugger auto-discovery: resolve auth server from protected-resource metadata by @Vu-John in #2881
• fix(inspector): keep bearer token visible after save by @ignaciojimenezr in #2772
• make home tab be able to use users mcp servers by @ignaciojimenezr in #2864
• Revert "make home tab be able to use users mcp servers" by @chelojimenez in #2884
• [XAA] Send the flow's subject in negative-test scorecard runs by @Vu-John in #2887
• Unify playground client + model selection into one run picker by @ignaciojimenezr in #2886
• slackbot client template by @ignaciojimenezr in #2889
• mistral csp by @ignaciojimenezr in #2892
• remove host styles from playground by @ignaciojimenezr in #2894
• changesets by @ignaciojimenezr in #2896

Full Changelog: v2.18.2...v2.19.0