refactor: username sub route (#39967)

Remove the workaround for chi router, do as much as possible in
middlewares

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>

services/context/user.go

@@ -8,10 +8,22 @@ import (
 	"net/http"
 	"strings"
 
+	"gitea.dev/models/organization"
 	user_model "gitea.dev/models/user"
 	"gitea.dev/modules/session"
 )
 
+func ReqContextUserVisibleToDoer() func(ctx *Context) {
+	return func(ctx *Context) {
+		isOrg := ctx.ContextUser.IsOrganization()
+		if isOrg && !organization.HasOrgOrUserVisible(ctx, ctx.ContextUser, ctx.Doer) ||
+			!isOrg && !user_model.IsUserVisibleToViewer(ctx, ctx.ContextUser, ctx.Doer) {
+			ctx.NotFound(nil)
+			return
+		}
+	}
+}
+
 // UserAssignmentWeb returns a middleware to handle context-user assignment for web routes
 func UserAssignmentWeb() func(ctx *Context) {
 	return func(ctx *Context) {