Add a workflow that fires on the `issues: labeled` event and, when the added
label is `regression`, posts an alert to a dedicated Discord channel via the
DISCORD_WEBHOOK_REGRESSION secret. This gives the team a real-time ping
whenever the Oz triage agent or a maintainer tags a regression.
Issue fields are passed through env vars and read with `jq --arg` rather than
inlined into the shell, so a crafted issue title cannot inject shell code.
`allowed_mentions: {parse: []}` prevents a title like `@everyone` from pinging
the server, and the job runs with empty permissions since the only outbound
call is the webhook. The step is skipped when the secret is unset.
Also fix the regression report issue template, which declared the nonexistent
`type: regression` label; the real repository label is `regression`. Aligning
the template means template-filed reports are auto-labeled and therefore
auto-announced.
Zoltan Kochan
1d3c3d808f