refactor: bundle MCP servers inside plugins for cache compatibility

Claude Code only caches the plugin directory when installed from a
marketplace, not parent directories. This broke the shared mcp-servers/
architecture because relative paths like ../../mcp-servers/ resolved
to non-existent locations in the cache.

Changes:
- Move gitea and wikijs MCP servers into plugins/projman/mcp-servers/
- Move netbox MCP server into plugins/cmdb-assistant/mcp-servers/
- Update .mcp.json files to use ${CLAUDE_PLUGIN_ROOT}/mcp-servers/
- Update setup.sh to handle new bundled structure
- Add netbox.env config template to setup.sh
- Update CLAUDE.md and CANONICAL-PATHS.md documentation

This ensures plugins work correctly when installed and cached.

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

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

mcp-servers/netbox/requirements.txt

@@ -1,6 +0,0 @@
-mcp>=0.9.0               # MCP SDK from Anthropic
-python-dotenv>=1.0.0     # Environment variable loading
-requests>=2.31.0         # HTTP client for NetBox API
-pydantic>=2.5.0          # Data validation
-pytest>=7.4.3            # Testing framework
-pytest-asyncio>=0.23.0   # Async testing support