feat: publish Tend v0.2 Preview 2 source

Export the reviewed allowlisted snapshot from private source commit 8aab3db43f35e6a49aa497f45d73701b13fc9f32 and tree 992132ea4703437dc13ffdbb04a077816c02caf9. This includes routed singleton continuity, deployment evidence, strict schema-2 configuration, restricted transport, and the independently compilable public-tree guard.

AI-Assisted: OpenAI Codex
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

examples/blue-green/tend.json

@@ -7,9 +7,11 @@
     "root": "/opt/example-site",
     "lock_file": "/run/lock/tend-deploy.lock",
     "state_file": "/opt/example-site/tend-state.json",
+    "event_log": "/opt/example-site/deployment-events.jsonl",
     "health_path": "/healthz",
     "readiness_path": "/readyz",
     "candidate_timeout_seconds": 30,
+    "activation_window_seconds": 10,
     "smoke": [{ "path": "/", "contains": "Example site" }],
     "public_smoke": [{ "url": "https://example.test/", "contains": "Example site" }],
     "blue_green": {