refactor(auth): delegate access control to be-system

Remove Agent Desk users, roles, login sessions, tokens, and local permission persistence. Expose the backend as an embeddable ai-agent module with host-provided subject lookup and operation authorization callbacks, and complete the frontend/backend repository split.

internal/ai/runtime/tooling/tool_result_reducer.go

@@ -7,7 +7,7 @@ import (
 	"strconv"
 	"strings"
 
-	"agent-desk/internal/ai/mcps"
+	"code.tczkiot.com/wlw/ai-agent/internal/ai/mcps"
 )
 
 const (

internal/ai/runtime/tooling/tool_result_reducer_test.go

@@ -4,7 +4,7 @@ import (
 	"strings"
 	"testing"
 
-	"agent-desk/internal/ai/mcps"
+	"code.tczkiot.com/wlw/ai-agent/internal/ai/mcps"
 )
 
 func TestBuildReducedToolResultSummaryDeduplicatesStructuredAndTextContent(t *testing.T) {