feat: harden support, localize knowledge and add operator availability [skip ci]

Source-only publication of reviewed commit 64e96a7f423673dc29ad56485be9fc79bce8af1c.

Passed in isolation: focused frontend/backend tests, race checks, TypeScript typecheck, lint, Go compilation, Flowgram build, and deterministic SDK build/tests.

Not accepted as a production release: Next.js export/native assembly remains blocked by environment memory limits; browser interaction and MySQL staging acceptance remain unverified. No production server, database/schema, runtime configuration, deployment, release tag, or workflow execution was performed.

Expected source tree: 0a4a7528e9.

internal/pkg/dto/response/setup_readiness_resp.go

@@ -1,3 +1,4 @@
+// Modified in AgentDeskFixes: safe, reviewed setup repairs and honest routing diagnostics.
 package response
 
 type SetupIssueItem struct {
@@ -92,7 +93,20 @@ type SetupSimulateRouteResponse struct {
 	CandidateOperators []SimulatedOperatorCandidate `json:"candidate_operators"`
 }
 
-type SetupQuickFixResponse struct {
-	AppliedActions []string               `json:"applied_actions"`
-	Readiness      SetupReadinessResponse `json:"readiness"`
+type SetupQuickFixChange struct {
+	EntityType string         `json:"entity_type"`
+	EntityID   int64          `json:"entity_id"`
+	EntityName string         `json:"entity_name"`
+	Operation  string         `json:"operation"`
+	Before     map[string]any `json:"before"`
+	After      map[string]any `json:"after"`
+}
+
+type SetupQuickFixResponse struct {
+	Applied        bool                    `json:"applied"`
+	PreviewToken   string                  `json:"preview_token"`
+	Changes        []SetupQuickFixChange   `json:"changes"`
+	WarningCodes   []string                `json:"warning_codes"`
+	AppliedActions []string                `json:"applied_actions"`
+	Readiness      *SetupReadinessResponse `json:"readiness,omitempty"`
 }