feat: first-contact bootstrap play (named admin + SSH key import)

Implements Task 4 (the play was run on-site but never committed). Creates the
named admin user, imports the operator pubkey over SCP (net_put), enables SSH.
Improvements over the plan: the key import is :if [find] guarded so re-runs don't
create duplicate keys, and the vaulted password is loaded via vars_files (it is
not auto-loaded because group_vars/mikrotik.vault.yml doesn't match the group-name
convention). Verified idempotent (changed=0) against crs310-maker; no duplicate key.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

play_bootstrap.yml

@@ -0,0 +1,52 @@
+---
+# FIRST-CONTACT bootstrap (run once, password auth):
+#   ansible-playbook play_bootstrap.yml -e ansible_user=admin --ask-pass
+# Creates the named admin user, imports the operator SSH public key over SCP, and
+# enables SSH so day-2 runs (play_switch.yml) can use key auth as that user.
+# Keep a WinBox MAC / serial recovery channel open while running this.
+#
+# vault_switch_admin_password is decrypted automatically from
+# group_vars/mikrotik.vault.yml via the `makerfloss` vault id in ansible.cfg.
+# All device-touching tasks are :if [find] guarded, so the play is safe to re-run.
+- name: Bootstrap MikroTik switch (first contact, password auth)
+  hosts: mikrotik
+  gather_facts: false
+  # The vaulted admin password is NOT auto-loaded: group_vars/mikrotik.vault.yml
+  # doesn't match the group-name convention (only mikrotik.yml or group_vars/mikrotik/
+  # auto-load), so load it explicitly here. Day-2 (play_switch.yml) is key auth and
+  # needs no secret. Decrypted automatically via the makerfloss vault id in ansible.cfg.
+  vars_files:
+    - group_vars/mikrotik.vault.yml
+  vars:
+    pubkey_local: "{{ switch_admin_ssh_pubkey_file | default('~/.ssh/id_ed25519.pub') }}"
+    pubkey_remote: "id_ansible.pub"
+  tasks:
+    - name: Create named admin user (idempotent)
+      community.routeros.command:
+        commands:
+          - >-
+            :if ([:len [/user find name="{{ switch_admin_user }}"]] = 0)
+            do={ /user add name="{{ switch_admin_user }}"
+            group="{{ switch_admin_group | default('full') }}"
+            password="{{ vault_switch_admin_password }}" }
+      changed_when: false
+
+    - name: Copy operator public key to the switch
+      ansible.netcommon.net_put:
+        src: "{{ pubkey_local }}"
+        dest: "{{ pubkey_remote }}"
+
+    - name: Import the SSH public key for the admin user (only if none yet)
+      community.routeros.command:
+        commands:
+          - >-
+            :if ([:len [/user/ssh-keys/find user="{{ switch_admin_user }}"]] = 0)
+            do={ /user/ssh-keys/import public-key-file="{{ pubkey_remote }}"
+            user="{{ switch_admin_user }}" }
+      changed_when: false
+
+    - name: Ensure SSH service is enabled
+      community.routeros.command:
+        commands:
+          - /ip/service/set ssh disabled=no port={{ switch_ssh_port | default(22) }}
+      changed_when: false