fix: show proper validation error message when user inputs old path in redirect section (#5082)

## Description

fixes: #5050 

fixes the validation error message when user enters old path in
redirects section.


![image](https://github.com/user-attachments/assets/e4f2793d-5179-467d-9655-95247b9e8439)


## Steps for reproduction

1. go to project settings.
2. redirects tab
3. enter a url like https://website.org in old path input field.
4. the validation error will we shown in the tooltip.

## Code Review

- [ ] hi @kof, I need you to do
  - conceptual review (architecture, feature-correctness)
  - detailed review (read every line)
  - test it on preview

## Before requesting a review

- [x] made a self-review
- [x] added inline comments where things may be not obvious (the "why",
not "what")

## Before merging

- [x] tested locally and on preview environment (preview dev login:
0000)
- [ ] updated [test
cases](https://github.com/webstudio-is/webstudio/blob/main/apps/builder/docs/test-cases.md)
document
- [ ] added tests
- [ ] if any new env variables are added, added them to `.env` file

apps/builder/app/builder/features/project-settings/section-redirects.tsx

@@ -16,7 +16,7 @@ import {
 } from "@webstudio-is/design-system";
 import { ArrowRightIcon, TrashIcon } from "@webstudio-is/icons";
 import {
-  PagePath,
+  OldPagePath,
   PageRedirect,
   ProjectNewRedirectPath,
 } from "@webstudio-is/sdk";
@@ -58,7 +58,7 @@ export const SectionRedirects = () => {
   };
 
   const validateOldPath = (oldPath: string): string[] => {
-    const oldPathValidationResult = PagePath.safeParse(oldPath);
+    const oldPathValidationResult = OldPagePath.safeParse(oldPath);
 
     if (oldPathValidationResult.success === true) {
       if (oldPath.startsWith("/") === true) {

packages/sdk/src/schema/pages.ts

@@ -88,14 +88,10 @@ const HomePage = z.object({
   path: HomePagePath,
 });
 
-export const PagePath = z
+const DefaultPagePage = z
   .string()
   .refine((path) => path !== "", "Can't be empty")
   .refine((path) => path !== "/", "Can't be just a /")
-  .refine(
-    (path) => path === "" || path.startsWith("/"),
-    "Must start with a / or a full URL e.g. https://website.org"
-  )
   .refine((path) => path.endsWith("/") === false, "Can't end with a /")
   .refine((path) => path.includes("//") === false, "Can't contain repeating /")
   .refine(
@@ -114,6 +110,17 @@ export const PagePath = z
     "/build prefix is reserved for the system"
   );
 
+export const PagePath = DefaultPagePage.refine(
+  (path) => path === "" || path.startsWith("/"),
+  "Must start with a / or a full URL e.g. https://website.org"
+);
+
+// added this for old path input under redirect section of page settings
+export const OldPagePath = DefaultPagePage.refine(
+  (path) => path === "" || path.startsWith("/"),
+  "Must start with a / and it must be full path e.g. /project/id"
+);
+
 const Page = z.object({
   ...commonPageFields,
   path: PagePath,