feat(blocks): add reusable application shell blocks

- add appearance state, theme presets, preference controls, and preview components

- add responsive primary, nested, mobile, and flyout navigation with route-aware breadcrumbs

- add application layout, sidebar state, header actions, user menu, query refresh, and scroll utilities

- add configurable chat and notification surfaces backed by consumer-provided data and queries

- expose package entry points and cover theme, state, and command behavior with tests

packages/blocks/package.json

@@ -0,0 +1,44 @@
+{
+  "name": "@workspace/blocks",
+  "version": "0.0.0",
+  "type": "module",
+  "private": true,
+  "scripts": {
+    "format": "prettier --write \"**/*.{ts,tsx}\"",
+    "test": "vitest run",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@base-ui/react": "^1.6.0",
+    "@base-ui/utils": "^0.3.1",
+    "@floating-ui/utils": "^0.2.12",
+    "@hugeicons/core-free-icons": "^4.2.3",
+    "@hugeicons/react": "^1.1.9",
+    "@tanstack/react-hotkeys": "^0.10.0",
+    "@tanstack/react-query": "^5.101.4",
+    "@tanstack/react-router": "^1.170.18",
+    "@workspace/ui": "workspace:*",
+    "lucide-react": "^1.27.0",
+    "react": "^19.2.6",
+    "react-dom": "^19.2.6"
+  },
+  "devDependencies": {
+    "@testing-library/react": "^16.3.2",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
+    "jsdom": "^30.0.1",
+    "typescript": "~6",
+    "vitest": "^4.1.10"
+  },
+  "exports": {
+    "./globals.css": "./src/styles/globals.css",
+    "./appearance": "./src/blocks/appearance/index.ts",
+    "./chats": "./src/blocks/chats/index.ts",
+    "./components/*": "./src/components/*.tsx",
+    "./hooks/*": "./src/hooks/*.ts",
+    "./lib/*": "./src/lib/*.tsx",
+    "./layout": "./src/blocks/layout/index.ts",
+    "./navigation": "./src/blocks/navigation/index.ts",
+    "./notifications": "./src/blocks/notifications/index.ts"
+  }
+}