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

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({