svc-bkp-rmt-2-loc: migrate pull script to Python + add unit tests; lock down backup-provider ACLs

- Replace Bash pull-specific-host.sh with Python pull-specific-host.py (argparse, identical logic)
- Update role vars and runner template to call python script
- Add __init__.py files for test discovery/imports
- Add unittest: tests/unit/roles/svc-bkp-rmt-2-loc/files/test_pull_specific_host.py (mocks subprocess/os/time; covers success, no types, find-fail, retry-exhaustion)
- Backup provider SSH wrapper: align allowed ls path (backup-docker-to-local)
- Split user role tasks: 01_core (sudoers), 02_permissions_ssh (SSH keys + wrapper), 03_permissions_folders (ownership + default ACLs + depth-limited chown/chmod)
- Ensure default ACLs grant rwx to 'backup' and none to group/other; keep sudo rsync working

Ref: ChatGPT discussion (2025-10-14) — https://chatgpt.com/share/68ee920a-9b98-800f-8806-ddcfe0255149

roles/sys-bkp-provider-user/tasks/03_permissions_folders.yml

@@ -0,0 +1,64 @@
+# Ensure the backups root exists and is owned by backup
+- name: Ensure backups root exists and owned by backup
+  file:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    state: directory
+    owner: backup
+    group: backup
+    mode: "0700"
+
+# Explicit ACL so 'backup' has rwx, others none
+- name: Grant ACL rwx on backups root to backup user
+  ansible.posix.acl:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    entity: backup
+    etype: user
+    permissions: rwx
+    state: present
+
+# Set default ACLs so new entries inherit rwx for backup and nothing for others
+- name: Set default ACL (inherit) for backup user under backups root
+  ansible.posix.acl:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    entity: backup
+    etype: user
+    permissions: rwx
+    default: true
+    state: present
+
+# Remove default ACLs for group/others (defensive hardening)
+# Default ACLs so new entries inherit only backup's rwx
+- name: Default ACL for backup user (inherit)
+  ansible.posix.acl:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    etype: user
+    entity: backup
+    permissions: rwx
+    default: true
+    state: present
+
+# Explicitly set default group/other to no permissions (instead of absent)
+- name: Default ACL for group -> none
+  ansible.posix.acl:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    etype: group
+    permissions: '---'
+    default: true
+    state: present
+
+- name: Default ACL for other -> none
+  ansible.posix.acl:
+    path: "{{ BACKUPS_FOLDER_PATH }}"
+    etype: other
+    permissions: '---'
+    default: true
+    state: present
+
+- name: Fix ownership level 0..2 directories to backup:backup
+  ansible.builtin.shell: >
+    find "{{ BACKUPS_FOLDER_PATH }}" -mindepth 0 -maxdepth 2 -xdev -type d -exec chown backup:backup {} +
+
+- name: Fix perms level 0..2 directories to 0700
+  ansible.builtin.shell: >
+    find "{{ BACKUPS_FOLDER_PATH }}" -mindepth 0 -maxdepth 2 -xdev -type d -exec chmod 700 {} +
+