feat(monitoring): add Laravel Nightwatch monitoring support

- Install laravel/nightwatch package for application monitoring
- Create Nightwatch console command to start the monitoring agent
- Add NIGHTWATCH_ENABLED and NIGHTWATCH_TOKEN environment variables
- Configure nightwatch settings in config/constants.php
- Set up Docker s6-overlay services for both development and production
- Disable Nightwatch by default in test environment

docker/development/etc/s6-overlay/s6-rc.d/nightwatch-agent/dependencies.d/init-setup

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+

docker/development/etc/s6-overlay/s6-rc.d/nightwatch-agent/run

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+#!/command/execlineb -P
+
+# Use with-contenv to ensure environment variables are available
+with-contenv
+cd /var/www/html
+
+foreground {
+    php
+    artisan
+    start:nightwatch
+}
+

docker/development/etc/s6-overlay/s6-rc.d/nightwatch-agent/type

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+longrun

docker/development/etc/s6-overlay/s6-rc.d/user/contents.d/nightwatch-agent

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+