Deduplicate artifact bytes and deliver files by authenticated hash

src/lib/server/db/version-layout.ts

@@ -3,7 +3,7 @@ import type Database from 'better-sqlite3';
 /** Keep metadata ahead of overflow pages, preserving IDs and all references. */
 export function migrateVersionLayout(handle: Database.Database): void {
     const columns = handle.pragma('table_info(script_versions)') as { name: string }[];
-    if (columns.at(-1)?.name === 'content') return;
+    if (!columns.some(column => column.name === 'content') || columns.at(-1)?.name === 'content') return;
     const { sql } = handle.prepare("SELECT sql FROM sqlite_master WHERE name='script_versions'").get() as { sql: string };
     const content = /\bcontent\s+BLOB\s+NOT\s+NULL\s*,/i;
     if (!content.test(sql)) throw new Error('Unrecognized script version content layout');