Configure MCP servers to use Harbor OCI registry

- Updated Chart.yaml dependencies to use OCI registry
- Added HelmRepository resource for Harbor
- Created Harbor registry secret (SOPS-encrypted)
- Updated HelmRelease to use HelmRepository instead of Git source
- Packaged and pushed all 16 MCP charts to Harbor OCI registry
- Updated .sops.yaml to handle platform secrets

All MCP charts are now available at:
oci://images.caffeinetux.com/mcp-charts

.sops.yaml

@@ -1,4 +1,9 @@
 creation_rules:
+  # Platform secrets
+  - path_regex: platform/.*/.*secret.*\.yaml$
+    encrypted_regex: ^(data|stringData|password|token|apiKey|secret|key|auth|\.dockerconfigjson)$
+    age: age1c7ke5ajhtzua7lrvzsg2p7krnnqv5jhvafh4lsl2s022j46jggnss4rxry
+
   # Bootstrap secrets
   - path_regex: bootstrap/.*\.yaml$
     encrypted_regex: ^(data|stringData|password|token|apiKey|secret|key)$