refactor(bootstrap): standardize patterns, extract common logic, remove dead code

- Make timezone, locale, and keymap configurable via system_cfg
- Consolidate rhel8/9/10.repo.j2 into single rhel.repo.j2 template
- Extract bootstrap_common_conditional for shared firewall/LUKS/guest packages
- Remove redundant version aliases (fedora40-43, debian10-13, rhel8-10, etc.)
- Simplify bootstrap dispatch from 10 conditional blocks to single mapping
- Merge bootstrap_ubuntu_lts into bootstrap_ubuntu (identical)
- Remove orphaned firstrun.sh.j2 template
- Remove configuration/defaults/main.yml aliases, inline into banner.yml
- Remove unnecessary changed_when: false on set_fact/debug tasks
- Deduplicate hostname variable computation in locales.yml
- Update README with timezone/locale/keymap variable reference

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

roles/global_defaults/tasks/main.yml

@@ -2,7 +2,6 @@
 - name: Global defaults loaded
   ansible.builtin.debug:
     msg: Global defaults loaded.
-  changed_when: false
 
 - name: Normalize hypervisor inputs
   ansible.builtin.include_tasks: hypervisor.yml
@@ -17,7 +16,6 @@
   ansible.builtin.set_fact:
     is_rhel: "{{ os | lower in ['almalinux', 'fedora', 'rhel', 'rocky'] }}"
     is_debian: "{{ os | lower in ['debian', 'ubuntu', 'ubuntu-lts'] }}"
-  changed_when: false
 
 - name: Normalize OS version for keying
   when:
@@ -25,23 +23,6 @@
     - (os_version | string | length) > 0
   ansible.builtin.set_fact:
     os_version_major: "{{ (os_version | string).split('.')[0] }}"
-  changed_when: false
-
-- name: Resolve final OS key with version
-  when:
-    - os_version is defined
-    - (os_version | string | length) > 0
-  ansible.builtin.set_fact:
-    os_resolved: >-
-      {{
-        'debian' + os_version | string if os == 'debian'
-        else 'fedora' + os_version | string if os == 'fedora'
-        else 'rocky' + os_version_major if os == 'rocky'
-        else 'almalinux' + os_version_major if os == 'almalinux'
-        else 'rhel' + os_version_major if os == 'rhel'
-        else os
-      }}
-  changed_when: false
 
 - name: Set chroot command wrapper
   ansible.builtin.set_fact:
@@ -51,7 +32,6 @@
         if (system_cfg.features.chroot.tool | default('arch-chroot')) == 'systemd-nspawn'
         else (system_cfg.features.chroot.tool | default('arch-chroot')) ~ ' /mnt'
       }}
-  changed_when: false
 
 - name: Set Python interpreter for RHEL-based installers
   when:
@@ -59,7 +39,6 @@
     - is_rhel | bool
   ansible.builtin.set_fact:
     ansible_python_interpreter: /usr/bin/python3
-  changed_when: false
 
 - name: Set SSH access
   when:
@@ -70,10 +49,8 @@
     ansible_password: "{{ system_cfg.users[0].password }}"
     ansible_become_password: "{{ system_cfg.users[0].password }}"
     ansible_ssh_extra_args: "-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no"
-  changed_when: false
 
 - name: Set connection for VMware
   when: hypervisor_type == "vmware"
   ansible.builtin.set_fact:
     ansible_connection: vmware_tools
-  changed_when: false