feat: US-011 — Global Tasks view UI

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -55,6 +55,7 @@
     "better-sqlite3": "^12.6.2",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
+    "date-fns": "^4.1.0",
     "drizzle-orm": "^0.45.1",
     "electron-squirrel-startup": "^1.0.1",
     "electron-store": "^8.2.0",
@@ -62,6 +63,7 @@
     "lucide-react": "^0.575.0",
     "radix-ui": "^1.4.3",
     "react": "^19.2.4",
+    "react-day-picker": "^9.13.2",
     "react-dom": "^19.2.4",
     "tailwind-merge": "^3.5.0",
     "tw-animate-css": "^1.4.0",