[BUG] Renaming a step falsely invalidates its tested status ("Test me")

Problem

Renaming a step (displayName-only edit) flips its badge from "Tested" to "Test me". Users read this as lost sample data and re-test every renamed step. Sample data is actually preserved (file id + payload verified live at 0.88.0 and identical on main). Present since 0.80.0 (5a198942a2).

Ref: Pylon 5479

Root cause

_updateAction / _updateTrigger stamp lastUpdatedDate: dayjs().toISOString() on every update, including displayName-only ones:

• packages/core/execution/src/lib/flows/operations/update-action.ts:19
• packages/core/execution/src/lib/flows/operations/update-trigger.ts:17

Badge condition: lastUpdatedDate > lastTestDate → "Test me" (packages/web/src/app/builder/flow-canvas/nodes/step-node/step-node-status-in-draft.tsx:131).

Fix

Keep the existing lastUpdatedDate when the request differs from the current step only in displayName (compare request vs existing step ignoring displayName and sampleData).

Steps to reproduce

1. Flow with tested trigger + action (both show "Tested")
2. Rename either step in the step-settings header
3. Badge flips to "Test me"; persists after reopening the flow

Repro evidence (0.88.0 image, API + UI): https://claude.ai/code/artifact/c8cfa21c-86d8-4e46-9181-72a77d7081f4a