Restructure repo into idiomatic Ansible layout, fix bugs, deduplicate charts

[Kimi450]

Restructure repo into idiomatic Ansible layout, fix bugs, deduplicate charts
Layout

• Move playbooks into playbooks/ with shorter names (e.g.
  install-and-configure-samba.yaml -> playbooks/samba.yaml)
• Move task includes into tasks/ and static assets into files/
• Rename group_vars/all -> group_vars/all.yaml
• Rename setup.yaml -> site.yaml (Ansible convention)
• Relocate deprecated spotify playbook under playbooks/deprecated/
  New files
• ansible.cfg: default inventory, no host-key check, SSH pipelining +
  ControlMaster, YAML stdout callback, smart gathering
• requirements.yml: declare kubernetes.core, community.general,
  ansible.posix (kubernetes.core was already used but never declared)
• tasks/process-persistence-disks.yaml: shared helper replacing six
  near-identical persistence-building blocks in charts.yaml

Bug fixes

• charts.yaml: remove stray '}' in four helm --set strings
  ({{ helm_common_persistence_downloads }}}) for readarr, lidarr,
  calibre-web, calibre
• deprecated/spotify.yaml: fix reference to non-existent
  tasks_clone_git_repo.yaml
• .gitignore: '*/kubespray/' is an invalid glob -> '/kubespray/';
  also add .venv/, *.retry, .ansible/, editor noise
• run.sh: fix broken command -v "ansible-playbook --version"
  check, add shebang, set -euo pipefail, cd to script dir, forward
  args via exec, install Galaxy collections from requirements.yml

Refactors

• charts.yaml (1248 -> 1041 lines): collapse six persistence blocks
  into one include_tasks loop
• kubernetes.yaml: rename the misleading "Install kubernetes using
  kubeadm" play (which ran regardless) to install cluster tooling;
  replace shell: curl | install for kubectl with uri + get_url;
  add creates: guard for Helm
• tasks/reload-systemd.yaml: replace 4-step shell: systemctl ...
  sequence with a single ansible.builtin.systemd_service call
• samba.yaml: shell: service smbd restart -> ansible.builtin.service
• deprecated/spotify.yaml: rewrite to use apt, copy, user, and the
  shared reload-systemd task instead of six raw shell: calls

README

• Add Repository Layout section with tree diagram
• Update all path references (group_vars/all.yaml, site.yaml,
  files/kubeadm-cp.bash, playbooks/cloudflare-dns-updater.yaml)
• Expand ./run.sh usage notes (--check, arg forwarding,
  PLAYBOOK/INVENTORY/VENV_DIR env overrides)

Verification

• ansible-playbook --syntax-check site.yaml -i hosts.yaml: OK
  (only pre-existing warnings for 'become'/'timeout' used as var
  names in include_tasks vars blocks)
• All 21 YAML files parse cleanly with PyYAML
• git detects every move as a rename; history preserved