refactor: simplify to independent multi-project structure

Removed npm workspace configuration in favor of simple multi-project repository.
Each project (web-app, housekeeping) is now completely self-contained.

## Changes
- Removed root package.json and package-lock.json
- Added VS Code workspace file for better project organization
- Updated documentation to reflect independent project structure
- Each project manages its own dependencies without workspace linking

## Structure
- web-app/: Self-contained Next.js application
- housekeeping/: Self-contained DB maintenance scripts
- No workspace management or dependency sharing
- Monorepo is purely for Git organization

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -1,17 +0,0 @@
-{
-  "name": "evidencija-rezija-monorepo",
-  "private": true,
-  "version": "2.20.0",
-  "workspaces": [
-    "web-app",
-    "housekeeping"
-  ],
-  "scripts": {
-    "dev": "npm run dev --workspace=web-app",
-    "build": "npm run build --workspace=web-app",
-    "start": "npm run start --workspace=web-app"
-  },
-  "engines": {
-    "node": ">=18.17.0"
-  }
-}