feat(pb,task): moves input validation into separated tasks files. Play fails immediately if a validation fails

tasks/hostname_validation.yaml

@@ -0,0 +1,23 @@
+--- 
+
+- name: Set default hostname
+  ansible.builtin.set_fact:
+    lxc_hostname: "new-lxc-test"
+
+- name: Prompt for hostname with immediate validation
+  ansible.builtin.pause:
+    prompt: "Enter hostname (letters, digits, hyphens, dots; max 253 chars) [new-lxc-test]"
+  register: hostname_result
+  until: >
+    hostname_result.user_input | length == 0 or
+    (
+      hostname_result.user_input | length <= 253 and
+      hostname_result.user_input is regex('^[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$')
+    )
+  retries: 2
+  delay: 0
+
+- name: Use user input only if provided, otherwise keep the default
+  ansible.builtin.set_fact:
+    lxc_hostname: "{{ hostname_result.user_input }}"
+  when: hostname_result.user_input | length > 0