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.
