recipe-maintainer: public snapshot (secrets + deployment plans removed, single commit)

Sanitized single-commit public mirror of recipe-maintainer.
- Removed test-ssh/.testenv (live creds); added test-ssh/.testenv.example placeholders.
- Removed plans/ and planned-updates/ (deployment-planning docs) so no client/
  deployment domains appear in the public repo.
- All other secret stores were already gitignored.
- docs.coopcloud.tech retained as a submodule (public upstream).

.opencode/skills/test-context-reset/SKILL.md

@@ -0,0 +1,6 @@
+---
+name: test-context-reset
+description: Undeploy all apps from the test server except traefik
+---
+Read and follow the full instructions in `.claude/commands/test-context-reset.md`.
+The optional recipe name to keep deployed will be provided by the user or calling agent.