refactor(standardize): remove dead code, fix inconsistencies, update docs

- Remove unused sudo_lecture.txt.j2 template (never referenced)
- Add vars_proxmox.yml and .sisyphus/ to .gitignore
- Remove redundant inner when conditions in cleanup/vmware.yml
- Standardize bootstrap_var_key usage in alpine, opensuse, void tasks
- Normalize sysctl key=value formatting (remove inconsistent spaces)
- Add vars_baremetal_example.yml to README examples list
- Remove unnecessary changed_when on set_fact in hypervisor.yml

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

.gitignore

@@ -6,3 +6,6 @@ vars.yml
 vars.yaml
 vars_kvm.yml
 vars_libvirt.yml
+vars_proxmox.yml
+
+.sisyphus/