Add ansible-managed wifi profiles for meshcore nodes

Each node now gets three NetworkManager wifi connections via a new
wifi role: dotnetwork (home), dotmobile (phone hotspot, for field
troubleshooting), and a host-specific deployed-location network.
Credentials live in a new per-repo ansible-vault (group and host
scoped), matching the pattern already used in dotnetwork.

Also updates the README's Pi imaging instructions from Bookworm to
Trixie, matching what the nodes actually run.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

ansible/host_vars/dm-ashwell/vars.yml

@@ -0,0 +1,5 @@
+serial_port: /dev/serial/by-id/usb-Espressif_USB_JTAG_serial_debug_unit_1C:DB:D4:5A:AA:B0-if00
+
+# Deployed-location wifi
+wifi_ssid_location: "awesome"
+wifi_password_location: "{{ vault_wifi_location }}"

ansible/host_vars/dm-ashwell/vault.yml

@@ -0,0 +1,7 @@
+$ANSIBLE_VAULT;1.1;AES256
+66323935356562383438383164383233366339616430313935613665376165393762633039663861
+3366373034613639386537363564643130653165393634370a326364323231306364313832366132
+65656264623537636264393433653838373234393435663838323263643037343637643139663838
+3932326163356663310a393065316631383230306433393063316135333030306531386138303733
+37363837376536323231386232333937306562343464376332386539323266653436643631353562
+3631616136623431626165336564643737306537643162666435