chore: add Kubernetes deployment manifests and Gitea Actions build workflow

Mirror the pr_reviewer deployment pattern: Gitea Actions builds a multi-arch
image in the gitea-runner namespace, pushes to git.aridgwayweb.com, recreates
the steward namespace with regcred + env secret, and applies kube manifests.
Add .omo/ to .gitignore.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

.gitignore

@@ -38,3 +38,6 @@ htmlcov/
 
 # MCP configuration (contains sensitive tokens)
 mcp.json
+
+# Local session tooling
+.omo/