feat: publish Tend v0.2 preview source

Publish the reviewed allowlisted snapshot whose exact binary completed maintenance deployment, rollback, and reactivation exercises for Gamertan and Sandwich Hime.

Private-Source-Commit: 4d7094c8b7c61991bfb67b11fc1558724c874eb2

Private-Source-Tree: 54a2f74804f7acddf3755d7d4da5b97f5fc28381

AI-Assistance: OpenAI Codex assisted implementation, testing, security review, and release verification.
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

examples/server/example-singleton.service

@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: 0BSD
+[Unit]
+Description=Example singleton site
+After=network.target
+
+[Service]
+Type=simple
+DynamicUser=yes
+ExecStart=/opt/example-site/current/example-site
+EnvironmentFile=/etc/tend/environment/example-site.env
+Environment=EXAMPLE_LISTEN=127.0.0.1:8092
+NoNewPrivileges=yes
+PrivateTmp=yes
+ProtectSystem=strict
+ProtectHome=yes
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target