Move fleet retention and concurrency controls into Settings

Persist settings in SQLite, import legacy environment values once, and apply changes to cleanup and deployment queues without restarting.

Closes #51

src/lib/server/provisioning/restarts.ts

@@ -1,4 +1,4 @@
-import { config } from '../config.js';
+import { fleetSettings } from '../settings.js';
 import { db } from '../db/index.js';
 import { komodoInspectHealthy, komodoRestart, komodoRuntimeAction } from '../integrations/komodo.js';
 import { probeServerStatus } from '../fleet/status-evidence.js';
@@ -49,7 +49,7 @@ export function rolloutWaitReason(server: string, operationId = ''): string | nu
         return `Waiting for the previous restart of this server to recover${slot.error ? `: ${slot.error}` : ''}`;
     }
     const { n } = db().prepare('SELECT COUNT(*) AS n FROM restart_rollout WHERE healthy_at IS NULL').get() as { n: number };
-    return n - (ownHandoff && slot?.healthy_at === null ? 1 : 0) >= config.restartConcurrency ? 'Queued for a rolling restart; waiting for another server to recover' : null;
+    return n - (ownHandoff && slot?.healthy_at === null ? 1 : 0) >= fleetSettings().restartConcurrency ? 'Queued for a rolling restart; waiting for another server to recover' : null;
 }
 
 export type RolloutRestartResult =