feat: add Proxmox VE API authentication and real data collection

Implement complete Proxmox API integration with support for both password
and API token authentication, replacing mock data with real infrastructure data.

**Authentication Features:**

1. **Dual Authentication Support**
   - API Token authentication (recommended, more secure)
   - Username + Password authentication (fallback)
   - Automatic fallback to mock data if not configured

2. **Configuration** (`src/datacenter_docs/utils/config.py`)
   - PROXMOX_HOST: Server hostname/IP
   - PROXMOX_PORT: API port (default 8006)
   - PROXMOX_USER: Username with realm (e.g., root@pam)
   - PROXMOX_PASSWORD: Password authentication
   - PROXMOX_TOKEN_NAME: API token name
   - PROXMOX_TOKEN_VALUE: API token secret
   - PROXMOX_VERIFY_SSL: SSL certificate verification
   - PROXMOX_TIMEOUT: API request timeout

3. **Real Data Collection** (`src/datacenter_docs/collectors/proxmox_collector.py`)
   - VMs: Iterate all nodes, collect QEMU VMs with full details
   - Containers: Collect LXC containers from all nodes
   - Nodes: Cluster node information and status
   - Cluster: Cluster configuration and quorum status
   - Storage: Storage pools with usage statistics
   - Networks: Network interfaces from all nodes
   - Automatic fallback to mock data on errors

4. **Comprehensive Documentation** (`docs/PROXMOX_SETUP.md`)
   - Step-by-step API token creation guide
   - Permission setup (PVEAuditor role)
   - Security best practices
   - Troubleshooting guide
   - Example configurations

5. **Environment Template** (`.env.example`)
   - Detailed Proxmox configuration section
   - Inline documentation for both auth methods
   - Security recommendations

**Security Features:**
- Supports read-only PVEAuditor role
- API tokens preferred over passwords
- SSL verification configurable
- Graceful degradation (uses mock data if API unavailable)
- No credentials in code (environment variables only)

**How to Configure:**

```bash
# Method 1: API Token (Recommended)
PROXMOX_HOST=proxmox.company.com
PROXMOX_USER=automation@pam
PROXMOX_TOKEN_NAME=docs-collector
PROXMOX_TOKEN_VALUE=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

# Method 2: Password
PROXMOX_HOST=proxmox.company.com
PROXMOX_USER=root@pam
PROXMOX_PASSWORD=your-secure-password
```

See `docs/PROXMOX_SETUP.md` for complete setup instructions.

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

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

.env.example

@@ -23,6 +23,36 @@ REDIS_URL=redis://redis:6379/0
 MCP_SERVER_URL=https://mcp.company.local
 MCP_API_KEY=your_mcp_api_key_here
 
+# =============================================================================
+# PROXMOX VE CONFIGURATION
+# =============================================================================
+# Proxmox server hostname or IP
+PROXMOX_HOST=proxmox.example.com
+PROXMOX_PORT=8006
+
+# Authentication Method 1: Username + Password (less secure)
+PROXMOX_USER=root@pam
+PROXMOX_PASSWORD=your-password-here
+
+# Authentication Method 2: API Token (RECOMMENDED, more secure)
+# To create an API token in Proxmox:
+# 1. Login to Proxmox web UI
+# 2. Go to Datacenter → Permissions → API Tokens
+# 3. Click "Add" and create a new token (e.g., "automation@pam!docs-collector")
+# 4. Copy the token secret (shown only once!)
+# 5. Set privileges: Datacenter → Permissions → add "/", "PVEAuditor" role
+#
+# Format: user@realm!tokenname
+# PROXMOX_USER=automation@pam
+# PROXMOX_TOKEN_NAME=docs-collector
+# PROXMOX_TOKEN_VALUE=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+
+# SSL Verification (set to true in production with valid certificates)
+PROXMOX_VERIFY_SSL=false
+
+# API Timeout (seconds)
+PROXMOX_TIMEOUT=30
+
 # =============================================================================
 # LLM Configuration (OpenAI-compatible API)
 # Choose one of the configurations below and uncomment it