refactor(bootstrap,configuration,environment): add defaults/main.yml and extract hardcoded values

roles/bootstrap/defaults/main.yml

@@ -0,0 +1,15 @@
+---
+# OS → task file mapping for bootstrap dispatch.
+# Each key matches a supported `os` value; value is the task file to include.
+bootstrap_os_task_map:
+  almalinux: _dnf_family.yml
+  alpine: alpine.yml
+  archlinux: archlinux.yml
+  debian: debian.yml
+  fedora: _dnf_family.yml
+  opensuse: opensuse.yml
+  rocky: _dnf_family.yml
+  rhel: rhel.yml
+  ubuntu: ubuntu.yml
+  ubuntu-lts: ubuntu.yml
+  void: void.yml

roles/bootstrap/tasks/_normalize.yml

@@ -9,16 +9,3 @@
       Unsupported OS '{{ os | default("undefined") }}' for bootstrap.
       Supported: {{ bootstrap_os_task_map | dict2items | map(attribute='key') | join(', ') }}
     quiet: true
-  vars:
-    bootstrap_os_task_map:
-      almalinux: _dnf_family.yml
-      alpine: alpine.yml
-      archlinux: archlinux.yml
-      debian: debian.yml
-      fedora: _dnf_family.yml
-      opensuse: opensuse.yml
-      rocky: _dnf_family.yml
-      rhel: rhel.yml
-      ubuntu: ubuntu.yml
-      ubuntu-lts: ubuntu.yml
-      void: void.yml

roles/bootstrap/tasks/main.yml

@@ -31,18 +31,6 @@
 
 - name: Run OS-specific bootstrap process
   vars:
-    bootstrap_os_task_map:
-      almalinux: _dnf_family.yml
-      alpine: alpine.yml
-      archlinux: archlinux.yml
-      debian: debian.yml
-      fedora: _dnf_family.yml
-      opensuse: opensuse.yml
-      rocky: _dnf_family.yml
-      rhel: rhel.yml
-      ubuntu: ubuntu.yml
-      ubuntu-lts: ubuntu.yml
-      void: void.yml
     bootstrap_var_key: "{{ 'bootstrap_' + (os | replace('-lts', '') | replace('-', '_')) }}"
   ansible.builtin.include_tasks: "{{ bootstrap_os_task_map[os] }}"