Refactor AppURL usage (#30885)

Fix #30883
Fix #29591

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Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

services/context/base.go

@@ -254,7 +254,7 @@ func (b *Base) Redirect(location string, status ...int) {
 		code = status[0]
 	}
 
-	if strings.HasPrefix(location, "http://") || strings.HasPrefix(location, "https://") || strings.HasPrefix(location, "//") {
+	if !httplib.IsRelativeURL(location) {
 		// Some browsers (Safari) have buggy behavior for Cookie + Cache + External Redirection, eg: /my-path => https://other/path
 		// 1. the first request to "/my-path" contains cookie
 		// 2. some time later, the request to "/my-path" doesn't contain cookie (caused by Prevent web tracking)

services/context/context_response.go

@@ -52,7 +52,7 @@ func (ctx *Context) RedirectToCurrentSite(location ...string) {
 			continue
 		}
 
-		if !httplib.IsCurrentGiteaSiteURL(loc) {
+		if !httplib.IsCurrentGiteaSiteURL(ctx, loc) {
 			continue
 		}