Refactor project to modularize constants and utilities.

Moved reusable constants and helper functions to dedicated modules for improved maintainability and reusability. Improved build configuration to differentiate output directories for development and production. Enhanced server error handling and added safeguards for disabled web UI scenarios.

app/web/package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "build": "rollup -c",
     "dev": "rollup -c -w",
-    "start": "sirv public --no-clear"
+    "start": "sirv public --no-clear --single"
   },
   "devDependencies": {
     "@rollup/plugin-commonjs": "^24.0.0",