Add Tactical Monolith design system and landing page to web app

Set up Tailwind CSS v4 with full design token system from Stitch project
(obsidian surfaces, neon cyan/magenta/lime palette, Space Grotesk + Inter
typography, 0px border-radius). Landing page includes hero section, side
nav, module cards, system status panels, terminal log, and CRT overlay.

apps/web/package.json

@@ -10,9 +10,12 @@
     "test": "echo \"no tests yet\""
   },
   "dependencies": {
+    "@tailwindcss/postcss": "^4.2.2",
     "next": "^15.1.0",
+    "postcss": "^8.5.8",
     "react": "^19.0.0",
-    "react-dom": "^19.0.0"
+    "react-dom": "^19.0.0",
+    "tailwindcss": "^4.2.2"
   },
   "devDependencies": {
     "@types/node": "^22.10.0",