feat: restore cmdb-assistant plugin and fix marketplace paths

- Restored cmdb-assistant plugin from commit ba599e3
- Moved to plugins/cmdb-assistant/ following new structure
- Updated .mcp.json path to ../../mcp-servers/netbox
- Fixed marketplace.json paths for all plugins (now in plugins/)
- Updated README.md with cmdb-assistant link and structure
- Updated CLAUDE.md governance to include cmdb-assistant

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

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

plugins/cmdb-assistant/commands/cmdb-ip.md

@@ -0,0 +1,53 @@
+# CMDB IP Management
+
+Manage IP addresses and prefixes in NetBox.
+
+## Usage
+
+```
+/cmdb-ip <action> [options]
+```
+
+## Instructions
+
+You are an IP address management (IPAM) assistant with access to NetBox.
+
+### Actions
+
+**Prefixes:**
+- `prefixes` - List all prefixes using `ipam_list_prefixes`
+- `prefix <cidr>` - Get prefix details or find prefix containing address
+- `available in <prefix>` - Show available IPs in a prefix using `ipam_list_available_ips`
+- `create prefix <cidr>` - Create new prefix using `ipam_create_prefix`
+
+**IP Addresses:**
+- `list` - List all IP addresses using `ipam_list_ip_addresses`
+- `show <address>` - Get IP details
+- `allocate from <prefix>` - Auto-allocate next available IP using `ipam_create_available_ip`
+- `create <address>` - Create specific IP using `ipam_create_ip_address`
+- `assign <ip> to <device>` - Assign IP to device interface
+
+**VLANs:**
+- `vlans` - List VLANs using `ipam_list_vlans`
+- `vlan <id>` - Get VLAN details
+
+**VRFs:**
+- `vrfs` - List VRFs using `ipam_list_vrfs`
+
+### Workflow Examples
+
+**Allocate IP to new server:**
+1. Find available IPs in target prefix
+2. Create the IP address
+3. Assign to device interface
+
+## Examples
+
+- `/cmdb-ip prefixes` - List all prefixes
+- `/cmdb-ip available in 10.0.1.0/24` - Show available IPs
+- `/cmdb-ip allocate from 10.0.1.0/24` - Get next available IP
+- `/cmdb-ip assign 10.0.1.50/24 to web-server-01 eth0` - Assign IP to interface
+
+## User Request
+
+$ARGUMENTS