fix(web): move tsx to production dependencies for calendar generation

Calendar generation scripts need tsx at runtime to execute TypeScript files,
but tsx was in devDependencies which are not installed in production builds.

This caused calendar preview and PDF generation to fail in production with:
"EACCES: permission denied, mkdir '/nonexistent'" when trying to run npx tsx

Moving tsx to dependencies ensures it's available in production for:
- apps/web/scripts/generateCalendarComposite.tsx
- apps/web/scripts/generateCalendarAbacus.tsx

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/package.json

@@ -81,6 +81,7 @@
     "socket.io": "^4.8.1",
     "socket.io-client": "^4.8.1",
     "three": "^0.169.0",
+    "tsx": "^4.20.5",
     "y-protocols": "^1.0.6",
     "y-websocket": "^3.0.0",
     "yjs": "^13.6.27",
@@ -111,7 +112,6 @@
     "jsdom": "^27.0.0",
     "storybook": "^9.1.7",
     "tsc-alias": "^1.8.16",
-    "tsx": "^4.20.5",
     "typescript": "^5.0.0",
     "vitest": "^1.0.0"
   },