What's new in v0.2.78

A small hotfix on top of v0.2.77.

Cloud upgrade is now fully automatic for Pro users

v0.2.77 introduced a one-time heat-counter clamp that Pro users were asked
to run manually by opening the Railway dashboard and pasting a SQL
runbook. That was a mistake — the operation is idempotent, the data volume
is small, and Pre-Deploy has no concurrent users, so it should have been
shipped as a migration from day one.

v0.2.78 moves the clamp into migrations/023-heat-cap-clamp.sql. Railway
runs it automatically as part of Pre-Deploy when this version is pushed.
Pro users don't need to touch the dashboard.

If you already ran the v0.2.77 runbook by hand: re-running is harmless
(the migration is idempotent — zero rows changed on the second run).

No other changes

This release is a pure migration relocation. No code behavior changes from
v0.2.77.