Merged in feature/ai-instructions (pull request #3293)

chore: add ai instruction files

* chore: add ai instruction files

* let the instruction file apply to all files, not only ts files


Approved-by: Linus Flood

.github/copilot-instructions.md

@@ -0,0 +1,45 @@
+---
+applyTo: "{apps/scandic-web/**/*,apps/partner-sas/**/*,apps/scandic-redirect/**/*,packages/**/*}"
+---
+
+# Monorepo and Project Overview
+
+**OVERVIEW:** This is a monorepository managed by **[Turborepo]** containing Next.js applications and several shared internal packages.
+
+**PROJECT STRUCTURE:**
+
+- `/apps/*`: Where public-facing applications live.
+    - `/apps/scandic-web`: The public-facing site for Scandic Hotels. Displaing cms content from Contentstack, a hotel room booking flow, and user profile management. Hosted on Netlify.
+    - `/apps/partner-sas`: A whitelabel version of the Scandic site for SAS customers that mostly relates to booking a hotel room. Hosted on Netlify
+    - `/apps/scandic-redirect`: A service for handling redirects when a url doesn'
+      t match any static content or a page in Contentstack. Hosted on Netlify
+    - `/apps/redis-api`: An api that acts as a http front to Redis due to serveless constraints. Hosted as a container app in Azure.
+- `/packages/*`: Where shared code and utilities are stored. They are built with `transpilePackages` so they do not have their own build pipeline
+    - `/packages/design-system`: Shared React/UI components hosted as a Storybook.
+    - `/packages/trpc`: Shared trpc routers and logic.
+    - `/packages/tracking`: Shared tracking utilities and analytics.
+    - `/packages/booking-flow`: The main revenue-generating part where you find booking flow logic and related components.
+
+**INSTRUCTIONS FOR GENERATION:**
+
+1.  **Shared Code:** When generating code that could be reusable (components, hooks, utility functions, types), check the `/packages` directory for existing files. If a new, shared piece of logic is needed, generate it within the appropriate `/packages` subdirectory.
+2.  **Imports:** All imports from shared packages must use the configured package name (e.g., `import { Button } from '@repo/ui'`). **Do not use relative paths** to import code between apps and packages.
+3.  **Dependency Manager:** All package installations, script commands, and documentation examples must use **Yarn**.
+4.  **Testing:** All unit testing must use **Vitest**.
+
+## Next.js & React Best Practices
+
+**FRAMEWORK:** Next.js (Use **App Router**) and React.
+**LANGUAGE:** TypeScript with strict mode enabled.
+
+**COMPONENTS:**
+
+1.  **Default to Server Components:** All components in the `/app` directory are **Server Components** by default. Only use `'use client'` when necessary for interactivity (hooks, event handlers, etc.).
+2.  **Styling:** Use **Css Modules**.
+3.  **Immutability:** Never mutate props or state directly. Always return new objects or arrays for updates.
+4.  **Data Fetching** All client-side and server-side data fetching logic should use types and procedures defined in the shared /packages/trpc
+
+**FILE NAMING:**
+
+- Components: `PascalCase` (`ProductCard.tsx`).
+- Hooks: `camelCase` and start with `use` (`useUser.ts`).