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/group_vars/all/vars.yml

@@ -16,3 +16,8 @@ wifi_password_dotnetwork: "{{ vault_wifi_dotnetwork }}"
 
 wifi_ssid_dotmobile: "dotmobile"
 wifi_password_dotmobile: "{{ vault_wifi_dotnetwork }}"
+
+# meshcore-packet-capture install generation — see roles/meshcore_capture/tasks/main.yml.
+# New nodes get the current upstream layout by default; older nodes override
+# this to "legacy" in their own host_vars.
+meshcore_capture_layout: "system"