Add CLI support for creating and publishing templates

[m-abdelwahab]

Summary

Adds CLI support for creating, publishing/updating, unpublishing, and deleting Railway templates, matching the dashboard lifecycle while keeping the workflow usable for agents.

Changes

• Add railway templates create / generate

  • Creates an unpublished template draft from a project via templateGenerate
  • Matches the dashboard Generate Template action by passing project/environment context
  • Prompts for an omitted project in interactive mode
  • Supports --json output for agent workflows

• Add railway templates publish [template]

  • Publishes or updates a template via templatePublish
  • Accepts category, description, README, image, demo project, and workspace
  • Prompts for omitted template/metadata fields in interactive mode
  • Supports README via inline text, file, or stdin
  • Includes dashboard-aligned validation for category, description, README, and image
  • Supports clearing optional fields like --image ""

• Add railway templates update [template] as an alias for publish

  • Mirrors the dashboard behavior: marketplace template info updates go through templatePublish
  • Keeps the CLI wording clear when replacing metadata on an already published template
  • Uses the same user-auth refresh path as templates publish

• Add railway templates unpublish [template]

  • Unpublishes a published template via templateUnpublish
  • Prompts for template and confirmation in interactive mode
  • Requires --yes for non-interactive use
  • Supports --2fa-code and --json

• Add railway templates delete [template]

  • Deletes a template via templateDelete
  • Exposes delete, remove, and rm
  • Prompts for confirmation in interactive mode
  • Requires --yes for non-interactive use
  • Supports --2fa-code and --json

• Use user-scoped auth for template create/publish/update/unpublish/delete

  • Uses OAuth or RAILWAY_API_TOKEN
  • Avoids accidentally using project-scoped RAILWAY_TOKEN, since these template operations require user context
  • Threads the same user-auth client through project/workspace/template resolution used by these flows

• Add GraphQL operations for template generate, publish, unpublish, delete, lookup, and workspace-template lookup

Notes:

• A truly source-less empty service cannot currently generate a template; the backend returns that the service has no source usable for template generation. The live lifecycle test used nginx:latest as the smallest source-backed service.
• The dashboard also uses templatePublish for marketplace info updates; templateUpdateV2 exists, but it updates serialized template config/editor state rather than the publish metadata fields exposed by this CLI flow.