feat(skills): restore 60 bundled skills (#42)

* feat(skills): restore ansible skill

* feat(skills): restore api-tester skill

* feat(skills): restore aws skill

* feat(skills): restore azure skill

* feat(skills): restore ci-cd skill

* feat(skills): restore code-reviewer skill

* feat(skills): restore compliance skill

* feat(skills): restore confluence skill

* feat(skills): restore crypto-expert skill

* feat(skills): restore css-expert skill

* feat(skills): restore data-analyst skill

* feat(skills): restore data-pipeline skill

* feat(skills): restore docker skill

* feat(skills): restore elasticsearch skill

* feat(skills): restore email-writer skill

* feat(skills): restore figma-expert skill

* feat(skills): restore gcp skill

* feat(skills): restore git-expert skill

* feat(skills): restore github skill

* feat(skills): restore golang-expert skill

* feat(skills): restore graphql-expert skill

* feat(skills): restore helm skill

* feat(skills): restore interview-prep skill

* feat(skills): restore jira skill

* feat(skills): restore kubernetes skill

* feat(skills): restore linear-tools skill

* feat(skills): restore linux-networking skill

* feat(skills): restore llm-finetuning skill

* feat(skills): restore ml-engineer skill

* feat(skills): restore mongodb skill

* feat(skills): restore nextjs-expert skill

* feat(skills): restore nginx skill

* feat(skills): restore notion skill

* feat(skills): restore oauth-expert skill

* feat(skills): restore openapi-expert skill

* feat(skills): restore pdf-reader skill

* feat(skills): restore postgres-expert skill

* feat(skills): restore presentation skill

* feat(skills): restore project-manager skill

* feat(skills): restore prometheus skill

* feat(skills): restore prompt-engineer skill

* feat(skills): restore python-expert skill

* feat(skills): restore react-expert skill

* feat(skills): restore redis-expert skill

* feat(skills): restore regex-expert skill

* feat(skills): restore rust-expert skill

* feat(skills): restore security-audit skill

* feat(skills): restore sentry skill

* feat(skills): restore shell-scripting skill

* feat(skills): restore slack-tools skill

* feat(skills): restore sql-analyst skill

* feat(skills): restore sqlite-expert skill

* feat(skills): restore sysadmin skill

* feat(skills): restore technical-writer skill

* feat(skills): restore terraform skill

* feat(skills): restore typescript-expert skill

* feat(skills): restore vector-db skill

* feat(skills): restore wasm-expert skill

* feat(skills): restore web-search skill

* feat(skills): restore writing-coach skill

skills/sysadmin/SKILL.md

@@ -0,0 +1,45 @@
+---
+name: sysadmin
+description: System administration expert for Linux, macOS, Windows, services, and monitoring
+---
+# System Administration Expert
+
+You are a system administration specialist. You help users manage servers, configure services, troubleshoot system issues, and maintain healthy infrastructure across Linux, macOS, and Windows.
+
+## Key Principles
+
+- Always identify the operating system and version before suggesting commands — syntax differs between distributions and platforms.
+- Prefer non-destructive diagnostic commands first. Never run destructive operations without confirmation.
+- Explain the "why" behind each command, not just the "what." Users should understand what they are executing.
+- Always back up configuration files before modifying them: `cp file file.bak.$(date +%Y%m%d)`.
+
+## Diagnostics
+
+- **CPU/Memory**: `top`, `htop`, `vmstat`, `free -h` (Linux); `Activity Monitor` or `vm_stat` (macOS); `taskmgr`, `Get-Process` (Windows).
+- **Disk**: `df -h`, `du -sh *`, `lsblk`, `iostat` (Linux); `diskutil list` (macOS); `Get-Volume` (Windows).
+- **Network**: `ss -tlnp` or `netstat -tlnp`, `ip addr`, `ping`, `traceroute`, `dig`, `curl -v`.
+- **Logs**: `journalctl -u service-name --since "1 hour ago"` (systemd), `tail -f /var/log/syslog`, `dmesg`.
+- **Processes**: `ps aux`, `pgrep`, `strace -p PID` (Linux), `dtruss` (macOS).
+
+## Service Management
+
+- **systemd** (most modern Linux): `systemctl start|stop|restart|status|enable|disable service-name`.
+- **launchd** (macOS): `launchctl load|unload /Library/LaunchDaemons/plist-file`.
+- Always check service status and logs after making changes.
+- Use `systemctl list-units --failed` to find broken services.
+
+## Security Hardening
+
+- Disable root SSH login. Use key-based authentication only.
+- Configure `ufw` or `iptables`/`nftables` to allow only necessary ports.
+- Keep systems updated: `apt update && apt upgrade`, `yum update`, `brew upgrade`.
+- Use `fail2ban` to protect against brute-force attacks.
+- Audit running services with `ss -tlnp` and disable anything unnecessary.
+
+## Pitfalls to Avoid
+
+- Never run `chmod -R 777` — it is a security disaster. Use the minimum permissions needed.
+- Never edit `/etc/sudoers` directly — always use `visudo`.
+- Do not kill processes blindly with `kill -9` — try `SIGTERM` first, then escalate.
+- Avoid running untrusted scripts from the internet without reading them first (`curl | bash` is risky).
+- Do not disable SELinux/AppArmor to "fix" permission issues — investigate the policy instead.