Add a Render env variable to Terraform

This skill declares a new Terraform Cloud variable so a value can be set via the TFC UI and consumed by the Render backend services. It only does the plumbing — it does not wire the variable into a Render env group. Wiring requires picking the right *_config / *_secrets object in terraform/modules/render_service/, which is task-specific and the user should drive.

Inputs

The skill takes two positional args from the invocation: /render-env <name> <description>.

• ${name} — the Terraform variable name in snake_case. Used verbatim as the TFC variable key, the tfe_variable resource suffix, and the variable block name. Example: stripe_climate_api_key.
• ${description} — a short human-readable description. Used in the description attribute and (with the env appended) in the per-env tfe_variable description. Example: Stripe Climate API key.

If either arg is missing, ask the user before doing anything. Also ask:

• Sensitive? Default to true (almost everything in these files is sensitive). Only set false for non-secret config strings (cf. slo_report_slack_channel, customer_portal_url_overrides).
• Which environments? Default to all three (production, sandbox, test). The user may want to skip one — test in particular often omits variables that aren't exercised there.

Do not ask about lifecycle { ignore_changes = [value] }. New variables here have no value baked into the Terraform code, so there's nothing for Terraform to overwrite — TFC just holds whatever's typed into the UI, and ignore_changes would be a no-op. The handful of existing blocks that include it (e.g. polar_organization_id, customer_portal_url_overrides) seed a default value in code and want UI overrides to stick; that's a different shape from a fresh secret and the user will tell you up-front if they want it.

Naming convention