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).

.gitignore

@@ -0,0 +1,20 @@
+__pycache__
+target/
+bin/
+test-ssh/test-ssh-keys
+test-ssh/ssh-config
+archive/
+terraform/.testenv
+logs/
+recipes/
+.container-abra
+.idea
+references/
+settings.toml
+recipe-info/testsecrets/
+in-use/
+.claude/settings.local.json
+recipe-info/*/secrets.json
+recipe-info/*/*-credentials.*.toml
+recipe-info/*/test-account-*.json
+