Fix product URLs, prerender routes and links

Update routes and URL handling for product pages and improve prerender behavior. Changes include:

- data/pricing.json: change summer camp URL to the canonical "/summer-camp" path.
- nuxt.config.js: set prerender.failOnError = false and clean up the prerender routes list (replace old product slugs with new ones, remove duplicated entries, and consolidate gallery/news/calendar/stories routes).
- pages/destinations/[id].vue: switch product links to use a productUrl helper and add mapping rules so autumn-*/winter-* IDs route to /products/autumn and /products/winter, and the summer-camp ID routes to /summer-camp.

These changes align link generation with updated product routes and make prerendering more robust.

data/pricing.json

@@ -82,7 +82,7 @@
         "每期仅限8组家庭",
         "含爸妈托管时段"
       ],
-      "url": "/products/summer-camp"
+      "url": "/summer-camp"
     },
     {
       "id": "autumn",