Remove overridden puma.service.erb template

We remove our custom puma.service.erb template located at
lib/capistrano/templates, as the upstream capistrano3-puma gem (v6.2.0)
now supports all the adjustments we previously needed.

This template was originally copied and modified in
PR #5842 (Bump capistrano3-puma from 5.2.0 to 6.0.0),
with the following relevant changes:

1. WatchdogSec=0
We disabled systemd's watchdog feature by setting WatchdogSec=0.
This is now covered upstream since v6.1.0 via:
> <% if fetch(:puma_systemd_watchdog_sec) && fetch(:puma_systemd_watchdog_sec) > 0 %>
> WatchdogSec=<%= fetch(:puma_systemd_watchdog_sec) %>
> <% end %>

To preserve the same behavior, we now explicitly set:
> set :puma_systemd_watchdog_sec, 0
in config/deploy.rb, instead of relying on the template override.

2. SyslogIdentifier=puma
In our custom template, we replaced the default line:
> SyslogIdentifier=<%= fetch(:puma_service_unit_name) %>
with:
> SyslogIdentifier=puma

This was done to avoid introducing a new config variable
in the installer. However, now that we want to remove the overridden template,
we must accept the default behavior from the gem:
> set :puma_service_unit_name, -> { "puma_#{fetch(:application)}_#{fetch(:stage)}" }

As a result, the generated SyslogIdentifier will change from "puma" to something
like "puma_consul_staging".

The only implication is that we'll open a PR in the installer
to replace the hardcoded "puma" with the dynamic default,
so everything stays consistent.

Another option would be to override puma_service_unit_name
with "puma" to keep the SyslogIdentifier exactly as before.
However, this would also affect the names of the systemd services and sockets
(e.g., puma.service instead of puma_consul_staging.service),
which may lead to conflicts or require manual cleanup steps like disabling
and removing the old units. For now, we prefer to avoid that.

3. After=network.target
We had removed the "syslog.target" from the "After=" directive,
as we didn't depend on syslog.

However, keeping "After=syslog.target network.target" does not negatively impact us,
since Puma logs to files directly using StandardOutput=append:....
So we can also adopt the default value from template here.

4. ExecStart
In version 6.2.0, a small change was made to the template logic for the ExecStart line.
This change does not affect us. Since we don't define puma_use_login_shell,
the behavior remains exactly the same as before.

With these changes already supported in the gem, we no longer need
a local copy of the puma service template.

config/deploy.rb

@@ -56,6 +56,7 @@ set :puma_service_unit_name, -> { "puma_#{fetch(:application)}_#{fetch(:stage)}"
 set :puma_bind, "unix://#{shared_path}/tmp/sockets/puma.sock"
 set :puma_access_log, -> { File.join(shared_path, "log", "puma_access.log") }
 set :puma_error_log, -> { File.join(shared_path, "log", "puma_error.log") }
+set :puma_systemd_watchdog_sec, 0
 
 set :delayed_job_workers, 2
 set :delayed_job_roles, :background

lib/capistrano/templates/puma.service.erb

@@ -1,40 +0,0 @@
-# This file tells systemd how to run Puma as a 24/7 long-running daemon.
-#
-# Customize this file based on your bundler location, app directory, etc.
-# Customize and copy this into /usr/lib/systemd/system (CentOS) or /lib/systemd/system (Ubuntu).
-# Then run:
-#   - systemctl enable <%= fetch(:puma_service_unit_name) %>
-#   - systemctl {start,stop,restart} <%= fetch(:puma_service_unit_name) %>
-#
-#
-# Use `journalctl -u <%= fetch(:puma_service_unit_name) %> -rn 100` to view the last 100 lines of log output.
-#
-[Unit]
-Description=Puma HTTP Server for <%= "#{fetch(:application)} (#{fetch(:stage)})" %>
-<%= "Requires=#{fetch(:puma_service_unit_name)}.socket" if fetch(:puma_enable_socket_service) %>
-After=network.target
-
-[Service]
-Type=<%= service_unit_type %>
-WatchdogSec=0
-<%="User=#{puma_user(@role)}" if fetch(:puma_systemctl_user) == :system %>
-WorkingDirectory=<%= current_path %>
-ExecStart=<%= expanded_bundle_command %> exec puma -e <%= fetch(:puma_env) %>
-ExecReload=/bin/kill -USR1 $MAINPID
-<%- Array(fetch(:puma_service_unit_env_files)).each do |file| %>
-<%="EnvironmentFile=#{file}" -%>
-<% end -%>
-<% Array(fetch(:puma_service_unit_env_vars)).each do |environment_variable| %>
-<%="Environment=\"#{environment_variable}\"" -%>
-<% end -%>
-
-# if we crash, restart
-RestartSec=1
-Restart=on-failure
-
-<%="StandardOutput=append:#{fetch(:puma_access_log)}" if fetch(:puma_access_log) %>
-<%="StandardError=append:#{fetch(:puma_error_log)}" if fetch(:puma_error_log) %>
-
-SyslogIdentifier=puma
-[Install]
-WantedBy=<%=(fetch(:puma_systemctl_user) == :system) ? "multi-user.target" : "default.target"%>