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>

release/tend.json

@@ -1,6 +1,6 @@
 {
-  "schema_version": 1,
-  "service": { "name": "tend", "allowed_host": "localhost" },
+  "schema_version": 2,
+  "service": { "name": "tend", "allowed_host": "localhost", "environment_file": "/etc/tend/environment/tend-release-test.env" },
   "build": {
     "package": "./cmd/tend",
     "binary": "tend",
@@ -12,18 +12,18 @@
   "deployment": {
     "strategy": "singleton_candidate",
     "root": "/opt/tend-release-test",
-    "lock_file": "/run/lock/tend-release-test.lock",
+    "lock_file": "/run/lock/tend-deploy.lock",
     "state_file": "/opt/tend-release-test/tend-state.json",
     "health_path": "/healthz",
     "readiness_path": "/readyz",
     "candidate_timeout_seconds": 5,
     "smoke": [{ "path": "/", "contains": "Tend" }],
+    "public_smoke": [{ "url": "https://example.test/", "contains": "Tend" }],
     "singleton": {
       "unit": "tend-release-test.service",
       "address": "127.0.0.1:19090",
       "candidate_address": "127.0.0.1:19091",
       "listen_env": "TEND_RELEASE_TEST_LISTEN",
-      "environment": {},
       "current_link": "/opt/tend-release-test/current",
       "previous_link": "/opt/tend-release-test/previous"
     }