refactor: Webhooks (#12487)

Closes #12303

### What’s Changed
- Replace auto‐save with explicit Save / Cancel
Webhook forms now use manual “Save” and “Cancel” buttons instead of the
old debounced auto‐save/update.

- Separate “New” and “Detail” routes
Two dedicated paths `/settings/webhooks/new` for creation and
/`settings/webhooks/:webhookId` for editing, making the UX clearer.

- URL hint & normalization
If a user omits the http(s):// scheme, we display a “Will be saved as
https://…” hint and automatically default to HTTPS.

- Centralized validation with Zod
Introduced a `webhookFormSchema` for client‐side URL, operations, and
secret validation.

- Storybook coverage
Added stories for both “New Webhook” and “Webhook Detail”

- Unit tests
Added tests for the new `useWebhookForm` hook

packages/twenty-front/src/modules/app/components/SettingsRoutes.tsx

@@ -182,11 +182,19 @@ const SettingsObjects = lazy(() =>
   })),
 );
 
-const SettingsDevelopersWebhooksDetail = lazy(() =>
+const SettingsDevelopersWebhookNew = lazy(() =>
+  import(
+    '~/pages/settings/developers/webhooks/components/SettingsDevelopersWebhookNew'
+  ).then((module) => ({
+    default: module.SettingsDevelopersWebhookNew,
+  })),
+);
+
+const SettingsDevelopersWebhookDetail = lazy(() =>
   import(
     '~/pages/settings/developers/webhooks/components/SettingsDevelopersWebhookDetail'
   ).then((module) => ({
-    default: module.SettingsDevelopersWebhooksDetail,
+    default: module.SettingsDevelopersWebhookDetail,
   })),
 );
 
@@ -438,9 +446,13 @@ export const SettingsRoutes = ({
           path={SettingsPath.ApiKeyDetail}
           element={<SettingsDevelopersApiKeyDetail />}
         />
+        <Route
+          path={SettingsPath.NewWebhook}
+          element={<SettingsDevelopersWebhookNew />}
+        />
         <Route
           path={SettingsPath.WebhookDetail}
-          element={<SettingsDevelopersWebhooksDetail />}
+          element={<SettingsDevelopersWebhookDetail />}
         />
         <Route
           path={SettingsPath.Integrations}