Add prodnxsr0014-0019 physical nodes from cobbler

Six new bare-metal Dell OptiPlex 3070 hosts were racked and registered on
the legacy cobbler server; replicate their ENC classification here.

- Add prodnxsr0014-0019.main.unkin.net, role roles::base, environment develop
- Bump the prodnxsr node-count comment from 13 to 19

Claude-Session: https://claude.ai/code/session_01JUoARVdmhxKQHyyyp1pxeT

config/encapi/nodes.yaml

@@ -6,7 +6,7 @@
 # cobbler_mgmt_classes[0] (defaulting to roles::base if absent). See
 # ci/extract_incus_nodes.py, which regenerates this section.
 #
-# 13 prodnxsr* physical hypervisor/k8s nodes (environment=develop): NOT
+# 19 prodnxsr* physical hypervisor/k8s nodes (environment=develop): NOT
 # managed by the incus instance module; roles come from the PuppetDB
 # enc_role fact. Maintained by hand below.
 
@@ -442,3 +442,21 @@ prodnxsr0012.main.unkin.net:
 prodnxsr0013.main.unkin.net:
   role: roles::infra::incus::node
   environment: develop
+prodnxsr0014.main.unkin.net:
+  role: roles::base
+  environment: develop
+prodnxsr0015.main.unkin.net:
+  role: roles::base
+  environment: develop
+prodnxsr0016.main.unkin.net:
+  role: roles::base
+  environment: develop
+prodnxsr0017.main.unkin.net:
+  role: roles::base
+  environment: develop
+prodnxsr0018.main.unkin.net:
+  role: roles::base
+  environment: develop
+prodnxsr0019.main.unkin.net:
+  role: roles::base
+  environment: develop