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

tests/unit/deployment-collections.test.ts

@@ -51,6 +51,16 @@ function keysFor(preview: CollectionPreview) {
 }
 
 describe('multi-server blueprints', () => {
+    it('shows the saved startup limit in new previews and existing collection progress', async () => {
+        const { blueprint, preview } = await previewLineup();
+        const { queueCollection, getCollection, previewCollection } = await import('../../src/lib/server/fleet/collections.js');
+        const result = queueCollection({ previewId: preview.id, keys: keysFor(preview) });
+        const { fleetSettings, saveFleetSettings } = await import('../../src/lib/server/settings.js');
+        saveFleetSettings({ ...fleetSettings(), createConcurrency: 3 });
+        expect(previewCollection(blueprint.id).launchConcurrency).toBe(3);
+        expect(getCollection(result.collectionId!)?.queue.concurrency).toBe(3);
+    });
+
     it('saves a mixed-game lineup and previews unique slots and global ports without reserving them', async () => {
         const { blueprint, preview } = await previewLineup();
         const { db } = await import('../../src/lib/server/db/index.js');