Support multi-game betas with automatic server selection

src/lib/server/db/index.ts

@@ -125,9 +125,8 @@ function migrateTable(handle: Database.Database, table: string, cols: Array<{ na
 }
 
 // Backfill the multi-script join tables from the legacy single-script columns.
-// Idempotent — every INSERT is guarded by a NOT EXISTS clause on the target
-// row's primary key. Safe to run on every boot even after the deprecated
-// columns are eventually dropped.
+// Existing bundle membership is authoritative. Only single-script betas can
+// inherit server membership from the deprecated primary-script columns.
 function backfillMultiScriptJoins(handle: Database.Database): void {
     handle.exec(
         `INSERT INTO beta_scripts (beta_id, script_id, script_version_id)
@@ -144,9 +143,11 @@ function backfillMultiScriptJoins(handle: Database.Database): void {
          WHERE b.script_id IS NOT NULL
            AND bs.server_deleted_at IS NULL
            AND EXISTS (SELECT 1 FROM servers WHERE name = bs.server)
+           AND (SELECT COUNT(*) FROM beta_scripts x WHERE x.beta_id = b.id) = 1
+           AND EXISTS (SELECT 1 FROM beta_scripts x WHERE x.beta_id = b.id AND x.script_id = b.script_id)
            AND NOT EXISTS (
              SELECT 1 FROM beta_server_scripts x
-             WHERE x.beta_id = bs.beta_id AND x.server = bs.server AND x.script_id = b.script_id
+             WHERE x.beta_id = bs.beta_id AND x.server = bs.server
            )`
     );
     handle.exec(