Add complete UPS monitoring system with monthly battery testing

This commit adds a comprehensive UPS monitoring and management system for
the Proxmox cluster with automated shutdown orchestration and monthly
battery health testing.

Features:
- NUT (Network UPS Tools) configuration for INNO TECH USB UPS
- Automated cluster shutdown on power failure (3-minute grace period)
- Monthly automated battery testing with health evaluation
- Email notifications via PVE::Notify system
- WinNUT monitoring client for Windows VM 201

Components added:
- config/: NUT configuration files (ups.conf, upsd.conf, upsmon.conf, etc.)
- scripts/ups-shutdown-cluster.sh: Orchestrated cluster shutdown
- scripts/ups-monthly-test.sh: Monthly battery test with email reports
- scripts/upssched-cmd: Event handler for UPS state changes
- docs/: Complete installation and usage documentation

Key findings:
- UPS battery.charge reporting has 10-40 second delay after test start
- Test must monitor voltage drop (1.5-2V) and charge drop (9-27%)
- Battery health evaluation: EXCELLENT/GOOD/FAIR/POOR based on discharge rate
- Email notifications use Handlebars templates without Unicode emojis for compatibility

Configuration:
- UPS: INNO TECH (Voltronic protocol, vendor 0665:5161)
- Primary node: pvemini (10.0.20.201) with USB connection
- Monthly test: cron 0 0 1 * * /opt/scripts/ups-monthly-test.sh
- Shutdown timer: 180 seconds on battery before cluster shutdown

Documentation includes complete installation guides for NUT server,
WinNUT client, and troubleshooting procedures.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

proxmox/ups/config/upsd.users

@@ -0,0 +1,80 @@
+# Network UPS Tools: Example upsd.users
+#
+# This file sets the permissions for upsd - the UPS network daemon.
+# Users are defined here, are given passwords, and their privileges are
+# controlled here too.  Since this file will contain passwords, keep it
+# secure, with only enough permissions for upsd to read it.
+
+# --------------------------------------------------------------------------
+
+# Each user gets a section.  To start a section, put the username in
+# brackets on a line by itself.  To set something for that user, specify
+# it under that section heading.  The username is case-sensitive, so
+# admin and AdMiN are two different users.
+#
+# Possible settings:
+#
+# password: The user's password.  This is case-sensitive.
+#
+# --------------------------------------------------------------------------
+#
+# actions: Let the user do certain things with upsd.
+#
+# Valid actions are:
+#
+# SET   - change the value of certain variables in the UPS
+# FSD   - set the "forced shutdown" flag in the UPS
+#
+# --------------------------------------------------------------------------
+#
+# instcmds: Let the user initiate specific instant commands.  Use "ALL"
+# to grant all commands automatically.  There are many possible
+# commands, so use 'upscmd -l' to see what your hardware supports.  Here
+# are a few examples:
+#
+# test.panel.start      - Start a front panel test
+# test.battery.start    - Start battery test
+# test.battery.stop     - Stop battery test
+# calibrate.start       - Start calibration
+# calibrate.stop        - Stop calibration
+#
+# --------------------------------------------------------------------------
+#
+# Example:
+#
+#	[admin]
+#		password = mypass
+#		actions = SET
+#		instcmds = ALL
+#
+
+#
+# --- Configuring for a user who can execute tests only
+#
+#	[testuser]
+#		password  = pass
+#		instcmds  = test.battery.start
+#		instcmds  = test.battery.stop
+
+#
+# --- Configuring for upsmon
+#
+# To add a user for your upsmon, use this example:
+#
+#   [upsmon]
+#       password  = pass
+#       upsmon primary
+# or
+#       upsmon secondary
+#
+# The matching MONITOR line in your upsmon.conf would look like this:
+#
+# MONITOR myups@localhost 1 upsmon pass primary	(or secondary)
+#
+# See comments in the upsmon.conf(.sample) file for details about this
+# keyword and the difference of NUT secondary and primary systems.
+[admin]
+    password = parola99
+    actions = SET
+    instcmds = ALL
+    upsmon master