feat: add immediate context compaction API, UI button, and /compact slash command

- Add POST /bots/:bot_id/sessions/:session_id/compact endpoint for
  synchronous context compaction with fallback to chat model when no
  dedicated compaction model is configured
- Add "Compact Now" button to session info panel in the web UI
- Add /compact slash command for triggering compaction from chat
- Regenerate OpenAPI spec and TypeScript SDK

internal/command/commands.go

@@ -17,5 +17,6 @@ func (h *Handler) buildRegistry() *Registry {
 	r.RegisterGroup(h.buildFSGroup())
 	r.RegisterGroup(h.buildStatusGroup())
 	r.RegisterGroup(h.buildAccessGroup())
+	r.RegisterGroup(h.buildCompactGroup())
 	return r
 }