Add fleet and per-host concurrency controls

tests/unit/native-provisioning.test.ts

@@ -1372,3 +1372,21 @@ describe('cancelled native mutation bookkeeping', () => {
         expect(db().prepare('SELECT * FROM ec_host_ports WHERE host_id=?').all(hostId)).toHaveLength(delivered ? 0 : 2);
     });
 });
+
+describe('additional concurrency admission', () => {
+    it.each(['createConcurrencyPerHost', 'lifecycleConcurrency'] as const)('holds simultaneous startups with %s until recovery completes', async key => {
+        const first = await queue();
+        const { fleetSettings, saveFleetSettings } = await import('../../src/lib/server/settings.js');
+        saveFleetSettings({ ...fleetSettings(), createConcurrency: 5, [key]: 1 });
+        const { queueCreateServer } = await import('../../src/lib/server/provisioning/instances.js');
+        const second = queueCreateServer({ game: 't5', gameMode: 'zombie', mapSlug: 'theater', hostId, libraryId, image, plutoKey: 'second-key' });
+        if (!second.ok) throw new Error(second.message);
+        await advance();
+        const operations = [await operationFor(first.deploymentId), await operationFor(second.deploymentId)];
+        expect(operations.filter(Boolean)).toHaveLength(1);
+        expect((await detail(second.deploymentId)).stage).toContain('capacity');
+        saveFleetSettings({ ...fleetSettings(), [key]: 0 });
+        await advance();
+        expect(await operationFor(second.deploymentId)).not.toBeNull();
+    });
+});