refactor: update project data type

- add order property to set explicit ordering on projects page
- make project link optional as not all projects have an accessible link

src/lib/data-utils.ts

@@ -105,17 +105,12 @@ export async function getPostsByTag(
 
 export async function getAllProjects(): Promise<CollectionEntry<'projects'>[]> {
   const projects = await getCollection('projects')
-  return projects
-    .sort((a, b) => (b.data.startDate?.valueOf() ?? 0) - (a.data.startDate?.valueOf() ?? 0))
+  return projects.sort((a, b) => (a.data.order ?? Infinity) - (b.data.order ?? Infinity))
 }
 
-const FEATURED_PROJECT_IDS = ['homelab', 'chitai', 'cue', 'portfolio']
-
 export async function getFeaturedProjects(): Promise<CollectionEntry<'projects'>[]> {
   const projects = await getAllProjects()
-  return FEATURED_PROJECT_IDS
-    .map(id => projects.find(p => p.id === id))
-    .filter((p): p is CollectionEntry<'projects'> => p !== undefined)
+  return projects.slice(0, 4)
 }
 
 export async function getProjectsFeaturedTags(maxCount: number): Promise<string[]> {