devex: fix claude.md (#5439)

* feat: start on agents.md/claude.md

* feat: set up

* feat: api-client claude + skills

* feat: apps/frontend

* feat: skills list

* fix: lint issues

.claude/skills/tanstack-query/SKILL.md

@@ -0,0 +1,154 @@
+# TanStack Query
+
+TanStack Query (`@tanstack/vue-query` v5) is used for server state management — caching, background refetching, and cache invalidation. Use it instead of manual `ref()` + `await` patterns for any data that comes from an API.
+
+A TanStack MCP server is available — use `tanstack_doc` and `tanstack_search_docs` tools to look up API details when needed.
+
+## Setup
+
+TanStack Query is configured in `apps/frontend/src/plugins/tanstack.ts` as a Nuxt plugin with SSR hydration support. Default stale time is 5 seconds. The `QueryClient` is available via `useQueryClient()` or `useAppQueryClient()` (which also works in middleware).
+
+## Queries
+
+Use `useQuery` with the api-client for data fetching:
+
+```ts
+const client = injectModrinthClient()
+
+const { data, isPending, isError, error } = useQuery({
+	queryKey: ['project', 'v3', projectId],
+	queryFn: () => client.labrinth.projects_v3.get(projectId),
+	staleTime: 1000 * 60 * 5,
+})
+```
+
+In templates:
+
+```vue
+<span v-if="isPending">Loading...</span>
+<span v-else-if="isError">Error: {{ error.message }}</span>
+<div v-else>{{ data.title }}</div>
+```
+
+### Query Option Factories
+
+For queries used across multiple components, define reusable query option factories in `packages/ui/src/queries/`:
+
+```ts
+// composables/queries/project.ts
+export const STALE_TIME = 1000 * 60 * 5
+export const STALE_TIME_LONG = 1000 * 60 * 10
+
+export const projectQueryOptions = {
+	v3: (projectId: string, client: AbstractModrinthClient) => ({
+		queryKey: ['project', 'v3', projectId] as const,
+		queryFn: () => client.labrinth.projects_v3.get(projectId),
+		staleTime: STALE_TIME,
+	}),
+
+	members: (projectId: string, client: AbstractModrinthClient) => ({
+		queryKey: ['project', projectId, 'members'] as const,
+		queryFn: () => client.labrinth.projects_v3.getMembers(projectId),
+		staleTime: STALE_TIME,
+	}),
+}
+```
+
+Then use them:
+
+```ts
+const { data } = useQuery(projectQueryOptions.v3(projectId, client))
+```
+
+### Conditional Queries
+
+Use `enabled` as a computed for queries that depend on other data:
+
+```ts
+const { data: members } = useQuery({
+	queryKey: ['project', projectId, 'members'],
+	queryFn: () => client.labrinth.projects_v3.getMembers(projectId),
+	enabled: computed(() => !!projectId.value),
+})
+```
+
+## Mutations
+
+Use `useMutation` for create/update/delete operations. Invalidate related queries on success:
+
+```ts
+const queryClient = useQueryClient()
+const client = injectModrinthClient()
+
+const createMutation = useMutation({
+	mutationFn: (name: string) => client.archon.backups_v0.create(serverId, { name }),
+	onSuccess: () => queryClient.invalidateQueries({ queryKey: ['backups', 'list', serverId] }),
+})
+```
+
+Use `createMutation.isPending.value` to disable buttons during submission.
+
+### Optimistic Updates
+
+For mutations where responsiveness matters, use optimistic updates with rollback:
+
+```ts
+const patchMutation = useMutation({
+	mutationFn: async ({ projectId, data }) => {
+		await client.labrinth.projects_v3.patch(projectId, data)
+		return data
+	},
+
+	onMutate: async ({ projectId, data }) => {
+		await queryClient.cancelQueries({ queryKey: ['project', 'v3', projectId] })
+		const previous = queryClient.getQueryData(['project', 'v3', projectId])
+
+		queryClient.setQueryData(['project', 'v3', projectId], (old) => {
+			if (!old) return old
+			return { ...old, ...data }
+		})
+
+		return { previous }
+	},
+
+	onError: (_err, _variables, context) => {
+		if (context?.previous) {
+			queryClient.setQueryData(['project', 'v3', projectId], context.previous)
+		}
+	},
+
+	onSettled: () => {
+		queryClient.invalidateQueries({ queryKey: ['project', 'v3', projectId] })
+	},
+})
+```
+
+## Query Keys
+
+Keys use a hierarchical array pattern:
+
+```ts
+// Resource type → version/qualifier → ID
+['project', 'v3', projectId]
+
+// Resource type → ID → sub-resource
+['project', projectId, 'members']
+['project', projectId, 'versions', 'v3']
+
+// Domain → action → ID
+['backups', 'list', serverId]
+['tech-reviews']
+```
+
+Use `as const` for type safety. Put the resource ID last when possible — this makes partial key matching work for invalidation:
+
+```ts
+// Invalidates all project queries for this ID
+queryClient.invalidateQueries({ queryKey: ['project', projectId] })
+```
+
+## Key Files
+
+- `apps/frontend/src/plugins/tanstack.ts` — QueryClient setup + SSR hydration
+- `apps/frontend/src/composables/query-client.ts` — `useAppQueryClient()` helper
+- `apps/frontend/src/composables/queries/` — reusable query option factories