feat(gateway): add configurable lane queue mode, cap, and overflow

src/config/schema.test.ts

@@ -75,6 +75,29 @@ describe('configSchema — server', () => {
     expect(result.server.ws_rate_limit.violation_window_ms).toBe(2000);
   });
 
+  it('defaults queue settings', () => {
+    const result = configSchema.parse(minimalConfig);
+    expect(result.server.queue.mode).toBe('collect');
+    expect(result.server.queue.cap).toBe(50);
+    expect(result.server.queue.overflow).toBe('drop_old');
+  });
+
+  it('accepts custom queue settings', () => {
+    const result = configSchema.parse({
+      ...minimalConfig,
+      server: {
+        queue: {
+          mode: 'steer',
+          cap: 10,
+          overflow: 'drop_new',
+        },
+      },
+    });
+    expect(result.server.queue.mode).toBe('steer');
+    expect(result.server.queue.cap).toBe(10);
+    expect(result.server.queue.overflow).toBe('drop_new');
+  });
+
   it('defaults discovery settings', () => {
     const result = configSchema.parse(minimalConfig);
     expect(result.server.discovery.enabled).toBe(false);