Add SSH and hosts reference to infrastructure section

- Document ~/.hosts file with IP variables and helper functions
- Document SSH aliases from ~/.ssh/config
- Show primary SSH key (~/.ssh/homelab)
- Create central reference files table

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

CLAUDE.md

@@ -377,6 +377,42 @@ tests/
 
 Reference documentation: `~/Projects/homelab/`
 
+### Central Reference Files
+
+| File | Purpose | Usage |
+|------|---------|-------|
+| `~/.secrets` | API keys and passwords | `source ~/.secrets` |
+| `~/.hosts` | IPs, hostnames, URLs | `source ~/.hosts` |
+| `~/.ssh/config` | SSH aliases and keys | `ssh pve`, `ssh truenas` |
+
+### SSH Access
+
+**Primary key**: `~/.ssh/homelab` (used for all homelab hosts)
+
+```bash
+# Use aliases from ~/.ssh/config
+ssh pve              # Proxmox primary
+ssh pve2             # Proxmox secondary
+ssh truenas          # NAS
+ssh saltbox          # Media services
+ssh docker-host      # Docker services
+ssh lmdev1           # AI dev with GPU
+ssh trading-vm       # Trading with A6000
+ssh pihole           # DNS
+ssh traefik          # Reverse proxy
+```
+
+### Hosts Reference
+
+Source `~/.hosts` for IP variables:
+```bash
+source ~/.hosts
+curl http://$IP_TRUENAS:8080/api/...
+ping $IP_GATEWAY
+hosts_list    # Show all hosts
+hosts_check   # Ping critical hosts
+```
+
 ### API Credentials
 
 **Central secrets file**: `~/.secrets`