feat: migrate freecad-mcp to GitHub fork install and refactor deployments

- Switch freecad-mcp installation from PyPI to Heluca GitHub fork,
  using a configurable git ref (freecad_mcp_git_ref) instead of
  pinned PyPI version
- Retarget freecad-mcp deployment from Caliban to Larissa, update
  port from 22032 to 22063, and change service user to freecad-mcp
- Add git to apt dependencies for pip git+https installs
- Make deployment summary use inventory_hostname instead of hardcoded host
- Refactor kernos deploy to target all ubuntu hosts with service-based
  filtering via `services` host_var, replacing static host group

ansible/inventory/group_vars/all/vars.yml

@@ -40,6 +40,8 @@ freecad_mcp_version: 0.6.1
 openwebui_rel: 0.8.3
 pulseaudio_module_xrdp_rel: devel
 searxng_oauth2_proxy_version: 7.6.0
+# Git ref (branch, tag, or commit) - https://github.com/heluca/freecad-addon-robust-mcp-server
+freecad_mcp_git_ref: "main"
 
 # MCP URLs
 argos_mcp_url: http://miranda.incus:25534/mcp