Finish dm-edworth bootstrap: fix Tailscale install, add system-layout meshcore_capture support

- base: Tailscale's per-codename .nosetup.sh install scripts are gone
  (404); switch to the universal tailscale.com/install.sh, and split
  install/enable (always) from auth (only when a key is given) so a
  node without an authkey still gets Tailscale installed, just not
  authenticated.
- meshcore_capture: the current upstream installer (v2.0.0+, what a
  fresh install now produces) uses a completely different layout than
  dm-baldock/dm-ashwell's older flat ~/.meshcore-packet-capture setup —
  dedicated system user, /opt + /etc/meshcore-packet-capture,
  config.d/*.toml, meshcore-packet-capture.service. Added
  meshcore_capture_layout (system/legacy) so the role targets the right
  paths/service name per host without touching the two working legacy
  nodes. New 99-user.toml.j2 replicates the old MQTT broker coverage
  (letsmesh us/eu, meshrank, ukmesh, meshmapper) in the new config.d
  override format.
- dm-edworth: fill in serial_port now that the MeshCore device is
  connected; confirmed running and publishing to all 5 brokers.
- README: fix broken list formatting, document the installer's
  required manual step and why.

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

ansible/host_vars/dm-baldock/vars.yml

@@ -3,3 +3,6 @@ serial_port: /dev/serial/by-id/usb-Espressif_USB_JTAG_serial_debug_unit_98:3D:AE
 # Deployed-location wifi
 wifi_ssid_location: "H-NeT"
 wifi_password_location: "{{ vault_wifi_location }}"
+
+# Predates the current upstream installer's system-service layout
+meshcore_capture_layout: "legacy"