feat(opencode): add Twilio docs MCP

[xnoto]

Summary

• Adds the official public-beta twilio-docs remote MCP at https://mcp.twilio.com/docs using OpenCode's current direct mcp.<name> remote-server shape, with oauth: false and no headers.
• Documents the documentation-only boundary and packages a narrowly scoped Twilio troubleshooting skill that prohibits account access, API execution, credential reuse, and generic/API-capable Twilio MCPs.
• Bumps the immutable opencode-server chart from 0.1.66 to 0.1.67.

No linked issue; this is an owner-authorized configuration change.

Type of change

• Feature / enhancement
• Documentation
• GitOps desired state (manifests, kustomize, charts, SOPS/KSOPS secrets)

Validation

• Required pull-request checks pass — charts CI run 205 succeeded: repository hygiene, Helm validation, changed-chart detection, and opencode-server packaging. The post-publish GitOps update job was correctly skipped for this pull request.
• Generated or centrally distributed files were regenerated by their owning automation, not hand-edited — not applicable; all changes are authored chart content.
• Verified upstream Twilio documentation: current public-beta docs specify this exact OpenCode configuration and state that the hosted server is public-spec, read-only, and requires no authentication.
• Verified the OpenCode v1 schema used by the installed configuration accepts direct mcp.<name> remote entries with type, url, enabled, and oauth.

Impact and rollout

charts/opencode-server is the sole changed producer. On an explicitly approved merge, the main workflow would publish immutable chart 0.1.67 and automatically open or update a separate kustomize-cluster version-pin PR. That PR, its checks, merge, Argo reconciliation, pod rollout, cluster egress to mcp.twilio.com, and fresh-session MCP tool visibility remain separate, unperformed gates.

This PR does not publish, select a GitOps revision, deploy, sync Argo CD, restart OpenCode, or verify runtime connectivity. No changes were made to kustomize-cluster, tfroot-twilio, bridge charts, SOPS files, or runtime Secrets.

Safety and secrets

• Contains no plaintext secrets, decrypted SOPS values, state files, kubeconfigs, tokens, or private endpoints — manually inspected the complete diff; the only added endpoint is public https://mcp.twilio.com/docs with no embedded credentials.
• No local OpenTofu init/plan/apply/destroy/import/state operations were run or claimed — validation is delegated to pull-request CI.
• Breaking or irreversible effects are described above with rollback notes — no runtime change occurs from this PR; a post-deployment rollback, if ever needed, would be a separate reviewed GitOps pin to immutable 0.1.66 after confirming artifact availability.

AI agent materially authored this change; review is requested before any merge.

[github-actions]

Chart CI passed

Repository hygiene and Helm validation passed. View the workflow run.