feat(ui): Create content pattern components - DataTable, FilterBar, EmptyState, LoadingState

- Add LoadingState with table, card, list, and text skeleton patterns
- Add EmptyState with customizable icon, title, description, and action slot
- Add FilterBar with search input, clear button, and custom filter slot
- Add DataTable with TanStack Table integration, sorting, and row click
- Create barrel export index.ts for common components
- Install tanstack-table-8-svelte-5 for Svelte 5 compatibility
- Sync auth spec with authenticated user redirect requirements
- Archive p03-dashboard-enhancement

Refs: openspec/changes/p04-content-patterns
Closes: p04-content-patterns

frontend/package-lock.json

@@ -12,6 +12,7 @@
         "lucide-svelte": "^0.574.0",
         "recharts": "^2.15.1",
         "sveltekit-superforms": "^2.24.0",
+        "tanstack-table-8-svelte-5": "^0.1.2",
         "zod": "^3.24.2"
       },
       "devDependencies": {
@@ -5417,6 +5418,18 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/tanstack-table-8-svelte-5": {
+      "version": "0.1.2",
+      "resolved": "https://registry.npmjs.org/tanstack-table-8-svelte-5/-/tanstack-table-8-svelte-5-0.1.2.tgz",
+      "integrity": "sha512-wMRu7Y709GpRrbPSN6uiYPCsNk5J/ZjvNuHGCbSUNNZEs1u4q09qnoTbY1EcwGAb3RkDEHEyrE9ArJNT4w0HOg==",
+      "license": "MIT",
+      "dependencies": {
+        "@tanstack/table-core": "^8.20.5"
+      },
+      "peerDependencies": {
+        "svelte": "^5.0.0"
+      }
+    },
     "node_modules/tapable": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/tapable/-/tapable-2.3.0.tgz",