feat(labelprint): 4x6 label print proxy on a Raspberry Pi

A Pi 3B+ (stickah.local) shares a Phomemo PM246 to the LAN as a plain CUPS
queue, so any machine can print 4x6 labels -- fulfillr-site's shipping labels
in particular -- without installing the vendor driver, which is x86-64 only.
The role builds the TSPL CUPS driver from source instead.

It is Debian, not Fedora, so it lives in its own inventory and playbook
(make deploy-labelprint / check-labelprint) and the home.debyl.io roles can
never run against it. make bootfs renders its cloud-init first-boot files onto
a freshly imaged SD card from the same templates the role uses. The Wi-Fi
credentials for the home and rescue networks are in the vault.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ansible/deploy_labelprint.yml

@@ -0,0 +1,14 @@
+---
+# Label print proxy (Raspberry Pi 3B+, Raspberry Pi OS trixie).
+#
+# The Pi image itself is built by hand with rpi-imager and written to the SD
+# card outside of Ansible -- see roles/labelprint/README.md for what that image
+# has to contain. Everything from first boot onwards lives in the labelprint
+# role: the print driver, the CUPS queue, security updates, and the Wi-Fi
+# rescue access point.
+- hosts: labelprint
+  vars_files:
+    - vars/vault.yml
+  roles:
+    - role: labelprint
+      tags: labelprint