feat(01-02): create useProjects() composable with i18n support

- useProjects() returns projects, featuredProjects, filterByCategory, search, findById
- Added title/description/longDescription fields to Project interface
- Uses Nuxt auto-imports (computed, useI18n, Ref)
- i18n keys follow projects.${id}.title pattern

app/composables/useProjects.ts

@@ -0,0 +1,51 @@
+import { projects as projectsData } from '~/data/projects'
+import type { Project } from '~~/shared/types'
+
+/**
+ * Composable for accessing and filtering project data with i18n support.
+ * Titles, descriptions, and long descriptions are resolved via i18n keys.
+ */
+export function useProjects() {
+  const { t } = useI18n()
+
+  const projects = computed<Project[]>(() =>
+    projectsData.map((p) => ({
+      ...p,
+      title: t(`projects.${p.id}.title`),
+      description: t(`projects.${p.id}.description`),
+      longDescription: t(`projects.${p.id}.longDescription`) || undefined,
+    })),
+  )
+
+  const featuredProjects = computed(() => projects.value.filter((p) => p.featured))
+
+  function filterByCategory(category: string) {
+    return computed(() => projects.value.filter((p) => p.category === category))
+  }
+
+  function search(query: Ref<string> | string) {
+    return computed(() => {
+      const q = typeof query === 'string' ? query : query.value
+      if (!q) return projects.value
+      const lower = q.toLowerCase()
+      return projects.value.filter(
+        (p) =>
+          p.title.toLowerCase().includes(lower) ||
+          p.description.toLowerCase().includes(lower) ||
+          p.technologies.some((tech) => tech.toLowerCase().includes(lower)),
+      )
+    })
+  }
+
+  function findById(id: string) {
+    return computed(() => projects.value.find((p) => p.id === id))
+  }
+
+  return {
+    projects,
+    featuredProjects,
+    filterByCategory,
+    search,
+    findById,
+  }
+}