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);

src/config/schema.ts

@@ -32,6 +32,15 @@ const wsRateLimitSchema = z.object({
   violation_window_ms: z.number().min(1000).max(60000).default(10000),
 }).default({});
 
+const laneQueueSchema = z.object({
+  /** Queue behavior for concurrent requests in the same session lane. */
+  mode: z.enum(['collect', 'steer', 'interrupt']).default('collect'),
+  /** Max queued (pending) requests per lane. */
+  cap: z.number().min(1).max(1000).default(50),
+  /** Overflow strategy when cap is reached. */
+  overflow: z.enum(['drop_old', 'drop_new']).default('drop_old'),
+}).default({});
+
 const serverDiscoverySchema = z.object({
   /** Enable local-network service discovery (mDNS/Bonjour advertisement). */
   enabled: z.boolean().default(false),
@@ -59,6 +68,8 @@ const serverSchema = z.object({
   max_request_body_bytes: z.number().min(1024).max(10 * 1024 * 1024).default(1_048_576),
   /** Per-connection WebSocket ingress rate limit settings. */
   ws_rate_limit: wsRateLimitSchema,
+  /** Per-session gateway lane queue behavior. */
+  queue: laneQueueSchema,
   /** Optional Bonjour/mDNS advertisement settings. */
   discovery: serverDiscoverySchema,
 });