feat: v0.4.0 — Apache service stack, shell access, log viewer, changelog

Service stack (backend):
- webserver.ts rewritten: apache2/php-fpm routes replacing nginx; per-account
  Apache log endpoint; PHP-FPM reload per version; apache2ctl configtest/reload
- accounts.ts: added PUT /:id/shell to toggle /bin/bash vs /usr/sbin/nologin,
  runs usermod -s and writes audit log

New UI features (nixserver):
- ShellAccess page: grant/revoke SSH access per account via AccountPicker
- ApacheLogs page: live log viewer (access/error) per account; replaces stub
- NginxLogs: re-exports ApacheLogs (NixPanel uses Apache, not NGINX)
- WebServer page: shows apache2, php8.2-fpm, php8.3-fpm status with reload
  buttons; config test; Apache log viewer

Bug fixes:
- Accounts.tsx: Lucide icon size prop type widened (string|number); removed
  unused Users import; dropped duplicate NGINX log card
- Removed soon badge from ShellAccess and ApacheLogs entries

Project:
- CHANGELOG.md created with full history from 0.2.x through 0.4.0
- All packages bumped from 0.3.2 to 0.4.0

server/.env.example

@@ -0,0 +1,17 @@
+# Database (SQLite)
+# Production: DATABASE_URL="file:/opt/nixpanel/data/nixpanel.db"
+# Development: DATABASE_URL="file:./dev.db"
+DATABASE_URL="file:./dev.db"
+
+# JWT Secrets (generate with: openssl rand -hex 64)
+JWT_SECRET=""
+JWT_REFRESH_SECRET=""
+
+# Server
+PORT=4000
+HOST=127.0.0.1
+NODE_ENV=production
+
+# Licensing
+LICENSING_SERVER_URL="https://license.nixpanel.io"
+LICENSE_KEY=""