refactor: replace alice/bob with role-meaningful usernames (sys_admin, user01…)

[t0kubetsu]

Context

Several roles and scenario playbooks currently use alice and bob as VM user accounts. These names carry no meaning in a cyber range context and can be confusing when reading logs, Wazuh alerts, or CTF writeups.

Where it appears

range42-catalog:

• 02_ansible_layer/admin/roles/software.install.nodejs_app_systemd/defaults/main.yml
• 02_ansible_layer/admin/roles/software.install.warmup.dot_files/defaults/main.yml
• 02_ansible_layer/admin/roles/software.install.symlinks_farm/tasks/ubuntu/pentesting/_main.yml

range42-playbooks (demo_lab_network scenario):

• scenarios/demo_lab_network/04_ctf_infrastructure/stage_00/vuln_box_00.yml
• scenarios/demo_lab_network/04_ctf_infrastructure/stage_00/vuln_box_01.yml
• scenarios/demo_lab_network/04_ctf_infrastructure/stage_00/vuln_box_04.yml
• scenarios/demo_lab_network/04_ctf_infrastructure/stage_01/_r42_vuln_box_group.yml
• scenarios/demo_lab_network/02_admin_infrastructure/stage_00/*.yml

Proposed naming

Context	Current	Proposed
Vuln box OS user	alice	user or user01
Admin/deployer OS user	bob	sys_admin
Generic unprivileged user	alice	trainee or player
App service user	alice / bob	webapp_user (already used in some roles)

Exact names open for discussion — the goal is names that make the role of the account immediately obvious in logs and alerts.

Impact

• Roles that set defaults should expose the username as a variable so scenarios can override it without patching the role.
• Existing deployed labs are unaffected (change only applies on fresh deploy).
• SSH config templates and Wazuh alert rules that filter by username may need updating in range42-playbooks.