customer-blocklisted

# customer-block Rule 2 of the product-engineer skill on its own, for teams that want the block and nothing else. The full skill is `product-engineer` in the same repository. ## The block Every commit message and every pull request description ends with: ``` For the customer: What changed: <one or two sentences, no jargon, what they can now do or no longer suffer> Why it matters: <the benefit, in their terms> Automation effect: <only if a manual step disappeared or the system now handles more alone; otherwise omit the line> ``` Rules: no jargon a non-engineer would have to look up; a pure refactor gets one line under `What changed`; a bug fix says what the customer saw before and sees now; never invent an automation effect. Merge, fixup, squash and revert commits do not need the block. ## Two pairs A bug fix. Before: ``` fix(notifications): classify IsSystem events as idempotent and skip the badge increment ``` After: ``` fix(notifications): classify IsSystem events as idempotent and skip the badge increment For the customer: What changed: Things the system handles on its own no longer light up the phone or the menu badge; only items that need a person do. Why it matters: The badge count means "something needs you" again, so people stop ignoring it. Automation effect: Automatic housekeeping events are now fully handled without anyone looking at them. ``` A migration. Before: ``` chore: add composite index on (tenant_id, created_at) to bookings ``` After: ``` ch