TournamentBadgeOwner previously stored manual grants as N identical
rows to represent "this user has this badge N times" — one user had
12,345 duplicate rows for a single badge. This adds a `count` column,
collapses NULL-tournamentId duplicates in the backfill, and rewrites
the BadgeOwner view to expose count via SUM. The table shrinks from
75,596 to 24,204 rows. Also adds an index on TournamentBadgeOwner(userId)
as defense-in-depth for direct lookups, and updates replaceOwners to
dedupe ownerIds at insert time. Profile-page query for the worst-case
user drops from ~4 ms to ~1–2 ms warm.
Error: Invariant failed: Empty placements not supported
I don't think it's possible for this to happen normally
but this fix provides more defense just in case
