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>

SECURITY.md

@@ -4,11 +4,14 @@ Report suspected vulnerabilities privately to `security@sandwichhime.com`.
 Please include the affected Tend version, configuration shape, reproduction,
 and expected impact. Do not include production credentials or private logs.
 
-Tend treats source repositories, release artifacts, configuration, handwritten
-Caddy templates, and operators as trusted. It treats artifact paths, archives,
+Tend treats reviewed source, pinned toolchains, root-owned server policy and
+configuration, handwritten Caddy templates, and operators as trusted. It treats
+requested service names, protocol frames, artifact paths and bytes, archives,
 filesystem state, process output, HTTP responses, and deployment targets as
 adversarial inputs. It never evaluates configuration as shell code.
 
 The preview is not a sandbox and does not make an untrusted repository safe to
-build. Run `tend package` only for reviewed source. Production configuration
-must be root-owned and kept outside repositories.
+build. Run `tend package` only for reviewed source. Production configuration,
+receive policy, host keys, identities, and `0600` environment files stay outside
+repositories. A secret value appearing in a Tend report, artifact, state file,
+or process argument is a security defect and should be reported.