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/bootstrap/server.go

@@ -1,3 +1,4 @@
+// Modified in AgentDeskNext: authenticated support availability and calendars.
 package bootstrap
 
 import (
@@ -192,6 +193,7 @@ func addRouter(app *gin.Engine) {
 	dashboardGroup := app.Group("/api/dashboard", middleware.AuthMiddleware)
 	registerDashboardDashboardRoutes(dashboardGroup.Group("/dashboard"))
 	registerDashboardSetupRoutes(dashboardGroup.Group("/setup"))
+	registerDashboardSupportAvailabilityRoutes(dashboardGroup.Group("/support_availability"))
 	registerDashboardUserRoutes(dashboardGroup.Group("/user"))
 	registerDashboardOrganizationRoutes(dashboardGroup.Group("/organization"))
 	registerDashboardCompanyRoutes(dashboardGroup.Group("/company"))