Add session permission support to background agents for denying questions

Implements question-denied session permission rules when creating child
sessions via background task delegation. This prevents subagents from
asking questions by passing explicit permission configuration during
session creation.

🤖 GENERATED WITH ASSISTANCE OF OhMyOpenCode

src/features/background-agent/manager-session-permission.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, test } from "bun:test"
+import { tmpdir } from "node:os"
+
+import type { PluginInput } from "@opencode-ai/plugin"
+
+import { BackgroundManager } from "./manager"
+
+describe("BackgroundManager session permission", () => {
+  test("passes explicit session permission rules to child session creation", async () => {
+    // given
+    const createCalls: Array<Record<string, unknown>> = []
+    const client = {
+      session: {
+        get: async () => ({ data: { directory: "/parent" } }),
+        create: async (input: Record<string, unknown>) => {
+          createCalls.push(input)
+          return { data: { id: "ses_child" } }
+        },
+        promptAsync: async () => ({}),
+        abort: async () => ({}),
+      },
+    }
+    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput)
+
+    // when
+    await manager.launch({
+      description: "Test task",
+      prompt: "Do something",
+      agent: "explore",
+      parentSessionID: "ses_parent",
+      parentMessageID: "msg_parent",
+      sessionPermission: [
+        { permission: "question", action: "deny", pattern: "*" },
+      ],
+    })
+    await new Promise(resolve => setTimeout(resolve, 50))
+    manager.shutdown()
+
+    // then
+    expect(createCalls).toHaveLength(1)
+    expect(createCalls[0]?.body).toEqual({
+      parentID: "ses_parent",
+      title: "Test task (@explore subagent)",
+      permission: [
+        { permission: "question", action: "deny", pattern: "*" },
+      ],
+    })
+  })
+})