feat(gateway): support per-channel and per-session queue policy overrides

src/config/schema.test.ts

@@ -80,6 +80,8 @@ describe('configSchema — server', () => {
     expect(result.server.queue.mode).toBe('collect');
     expect(result.server.queue.cap).toBe(50);
     expect(result.server.queue.overflow).toBe('drop_old');
+    expect(result.server.queue.overrides.channels).toEqual({});
+    expect(result.server.queue.overrides.sessions).toEqual({});
   });
 
   it('accepts custom queue settings', () => {
@@ -98,6 +100,28 @@ describe('configSchema — server', () => {
     expect(result.server.queue.overflow).toBe('drop_new');
   });
 
+  it('accepts queue override settings', () => {
+    const result = configSchema.parse({
+      ...minimalConfig,
+      server: {
+        queue: {
+          overrides: {
+            channels: {
+              ws: { mode: 'collect', cap: 5 },
+            },
+            sessions: {
+              'ws:vip-user': { mode: 'interrupt', overflow: 'drop_new' },
+            },
+          },
+        },
+      },
+    });
+    expect(result.server.queue.overrides.channels.ws.mode).toBe('collect');
+    expect(result.server.queue.overrides.channels.ws.cap).toBe(5);
+    expect(result.server.queue.overrides.sessions['ws:vip-user'].mode).toBe('interrupt');
+    expect(result.server.queue.overrides.sessions['ws:vip-user'].overflow).toBe('drop_new');
+  });
+
   it('defaults discovery settings', () => {
     const result = configSchema.parse(minimalConfig);
     expect(result.server.discovery.enabled).toBe(false);

src/config/schema.ts

@@ -39,6 +39,25 @@ const laneQueueSchema = z.object({
   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'),
+  /** Optional per-channel/per-session queue policy overrides. */
+  overrides: z.object({
+    channels: z.record(
+      z.string(),
+      z.object({
+        mode: z.enum(['collect', 'steer', 'interrupt']).optional(),
+        cap: z.number().min(1).max(1000).optional(),
+        overflow: z.enum(['drop_old', 'drop_new']).optional(),
+      }),
+    ).default({}),
+    sessions: z.record(
+      z.string(),
+      z.object({
+        mode: z.enum(['collect', 'steer', 'interrupt']).optional(),
+        cap: z.number().min(1).max(1000).optional(),
+        overflow: z.enum(['drop_old', 'drop_new']).optional(),
+      }),
+    ).default({}),
+  }).default({}),
 }).default({});
 
 const serverDiscoverySchema = z.object({