Add Ansible playbooks for MeshCore monitoring node deployment

Roles: base (apt, tailscale, motd), meshcore_cli (pipx), meshcore_capture
(agessaman/meshcore-packet-capture + .env.local template), scripts (voltage, bandwidth).

Host vars contain per-device serial ports; group vars hold shared MQTT broker config.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ansible/roles/scripts/files/bandwidth.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+vnstat

ansible/roles/scripts/files/voltage.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+SCRIPT=$(basename "$0")
+
+# fetch status
+STATUS=$(vcgencmd get_throttled | cut -d "=" -f 2)
+
+# decode - https://www.raspberrypi.com/documentation/computers/os.html#get_throttled
+echo "vcgencmd get_throttled ($STATUS)"
+IFS=","
+for BITMAP in \
+   00,"currently under-voltage" \
+   01,"ARM frequency currently capped" \
+   02,"currently throttled" \
+   03,"soft temperature limit reached" \
+   16,"under-voltage has occurred since last reboot" \
+   17,"ARM frequency capping has occurred since last reboot" \
+   18,"throttling has occurred since last reboot" \
+   19,"soft temperature reached since last reboot"
+do set -- $BITMAP
+   if [ $(($STATUS & 1 << $1)) -ne 0 ] ; then echo "  $2" ; fi
+done
+
+echo "vcgencmd measure_volts:"
+for S in core sdram_c sdram_i sdram_p ; do printf '%9s %s\n' "$S" "$(vcgencmd measure_volts $S)" ; done
+
+echo "Temperature: $(vcgencmd measure_temp)"