DEVEX-1653: badge prod deploys as 🚂 RT or ⚡ Hotfix for P0 triage

[pdodgen-revparts]

Context

Peace Room ask (2026-07-09): during P0 triage the team needs to spot which prod deploys skipped the RT sign-off flow. Hotfixes see less scrutiny and are more likely culprits, but today the #releases notification looks identical for every prod deploy regardless of whether it came from the Thursday train or a direct-to-main dispatch. Wall of undifferentiated deploys is bad for triage speed.

Change

Adds a Classify deploy type step ahead of send-notification. Detection is pure regex on inputs.image_tag — no new inputs, no per-caller changes.

Rule: tag matches -rc.YYYY-MM-DD.N → 🚂 RT. Everything else → ⚡ Hotfix.

Verified against real tags from rt-2026-07-09 promote:

Tag	Classification
v0.440.10-rc.2026-07-09.7	🚂 RT
v4.7.0-rc.2026-06-18.3	🚂 RT
v12.221.30-rc.2026-06-18.2	🚂 RT (common)
v0.440.6-SHOP-5177-revert-ssr-sidecar.0	⚡ Hotfix
v0.439.9	⚡ Hotfix
v1.0.0	⚡ Hotfix

Message before / after

Before:

*webstore deployed by pdodgen*
    Version: `v0.440.10-rc.2026-07-09.7`
    View the Deployment
    View the Service APM
    View changes since v0.440.6-SHOP-5177-revert-ssr-sidecar.0

After (RT):

🚂 *RT* · *webstore deployed by pdodgen*
    Version: `v0.440.10-rc.2026-07-09.7`
    …

After (Hotfix):

⚡ *Hotfix* · *webstore deployed by pdodgen*
    Version: `v0.440.10`
    …

Fallback text field (used for mobile notifications + screen readers) also gets the badge as plain text (🚂 RT · webstore deployed).

Scoping notes

• Prod-only by structural design: this workflow is only invoked from prod deploy paths (deploy-eks.yaml → slack-notification). No env input, no gate needed — every message emitted here is a prod message. QA and staging notifications are unaffected.
• Jellyfish parser compatibility: per the earlier dual-tag-format work, the parser anchors on the Version line and repo name — not the header prefix. Added badge doesn't touch either. Safe.
• Non-RT repos (radmin, etc.): technically will show ⚡ Hotfix on every deploy since they never emit rc tags. Discussed and accepted — the label is honest (they're out-of-RT-process) and the badge cost is zero for repos that aren't triage-critical.

Verification plan

Once merged, watch #releases for the next RT-participant deploy (any env change) and confirm the badge renders correctly. If a rendering issue surfaces on mobile Slack, easy to iterate.

[cursor]

PR Summary

Low Risk
Notification-only change in a reusable workflow; classification is display-only and does not affect deploy behavior.

Overview
Prod deployment Slack notifications now prefix each message with 🚂 RT or ⚡ Hotfix so P0 triage can tell release-train deploys from out-of-band ones at a glance.

A new Classify deploy type step runs before the existing diff and send steps. It regex-matches inputs.image_tag: tags ending in -rc.YYYY-MM-DD.N are labeled release train; all other tags (plain semver, branch builds, etc.) are labeled hotfix. Outputs feed both the Block Kit header and the fallback text field (🚂 RT · repo deployed / ⚡ Hotfix · …). No new workflow inputs or caller changes.

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