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/src/routes/nixclient/cron.ts

@@ -121,7 +121,7 @@ async function writeCrontab(username: string, accountId: number): Promise<void>
     `# NixPanel crontab for ${username}`,
     `# DO NOT EDIT — managed by NixPanel`,
     '',
-    ...jobs.map(j => `${j.schedule} ${j.command}${j.comment ? ` # ${j.comment}` : ''}`),
+    ...jobs.map((j: { schedule: string; command: string; comment: string | null }) => `${j.schedule} ${j.command}${j.comment ? ` # ${j.comment}` : ''}`),
     '',
   ]