Two latent install-time issues that emitted scary postgres ERROR lines
on every fresh start but didn't actually break anything. MrGabri flagged
them after #494 had already cleared the FK-ordering crash.
1. Migration 035 builds three `CREATE INDEX` statements against
`backup_runs(created_at, …)`, but 029 creates the table with
`started_at` and no `created_at`. The wrapping try/catch silently
swallowed the resulting `column "created_at" does not exist` ERROR,
so the migration "succeeded" without ever creating the indexes.
Switched 035 to reference `started_at` (same chronological semantics)
and added migration 105 to create the same indexes idempotently for
deployments whose 035 already ran and silently failed.
2. `run-migrations-safe.js` snapshots `appliedFilenames` *before*
`detectExistingSchema()` runs. When `detectExistingSchema()` inserts a
row for e.g. `004_add_categories_and_cms.js` (because its tables exist
from a partially-completed prior install), the subsequent migration
loop still doesn't know about that insert, attempts the legacy
migration anyway, and its transaction-internal
`insert into migrations` conflicts with the row already there.
Re-query the applied set after detectExistingSchema so the loop sees
the corrected snapshot.
No behavioural change for healthy installs. New installs no longer log
the `column "created_at" does not exist` or `duplicate key value
violates unique constraint "migrations_filename_unique"` ERRORs.
Paul Nothaft
86b33d4dda