Preserve deleted server history

Retain historical server identities, results, and evidence after deletion. Mark archived entries as Deleted and prevent old work from targeting servers that reuse the same name.

Fixes #16.

src/lib/server/db/index.ts

@@ -7,6 +7,7 @@ import { requirement, type BetaPlan, type BetaRequirement } from '../../beta-pla
 import { emptyMetrics } from '../fleet/beta-evaluation.js';
 import { backfillLeaderboard } from '../fleet/leaderboard-ingest.js';
 import { initializeFleetSettings } from './fleet-settings.js';
+import { migrateServerHistory } from './server-history.js';
 
 let _db: Database.Database | null = null;
 
@@ -124,6 +125,8 @@ function backfillMultiScriptJoins(handle: Database.Database): void {
          FROM beta_servers bs
          JOIN betas b ON b.id = bs.beta_id
          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 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
@@ -329,6 +332,7 @@ export function db(): Database.Database {
             { name: 'mode', ddl: "ALTER TABLE server_launch_collections ADD COLUMN mode TEXT NOT NULL DEFAULT 'fill'" },
             { name: 'retained_servers', ddl: "ALTER TABLE server_launch_collections ADD COLUMN retained_servers TEXT NOT NULL DEFAULT '[]'" }
         ]);
+        migrateServerHistory(handle);
         migrateTable(handle, 'server_collection_previews', [
             { name: 'mode', ddl: "ALTER TABLE server_collection_previews ADD COLUMN mode TEXT NOT NULL DEFAULT 'fill'" },
             { name: 'fleet_snapshot', ddl: 'ALTER TABLE server_collection_previews ADD COLUMN fleet_snapshot TEXT' }