add systemd and launchd unit files, suppress unused warnings

docs/bw-agent.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=Bitwarden Desktop Agent
+After=graphical-session.target
+
+[Service]
+Type=simple
+ExecStart=%h/.local/bin/bw-agent --email %I
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=default.target

docs/com.bitwarden.agent.plist

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>Label</key>
+    <string>com.bitwarden.agent</string>
+    <key>ProgramArguments</key>
+    <array>
+        <string>/Users/USER/.local/bin/bw-agent</string>
+        <string>--email</string>
+        <string>USER@EXAMPLE.COM</string>
+    </array>
+    <key>RunAtLoad</key>
+    <true/>
+    <key>KeepAlive</key>
+    <true/>
+    <key>StandardErrorPath</key>
+    <string>/tmp/bw-agent.log</string>
+</dict>
+</plist>