fix(delegate-task): preserve native task metadata

src/plugin/tool-execute-after.test.ts

@@ -92,4 +92,34 @@ describe("createToolExecuteAfterHandler", () => {
     expect(output.title).toBe("stored title")
     expect(output.metadata).toEqual({ sessionId: "ses_native", agent: "hephaestus" })
   })
+
+  it("#given native session linkage without model #when stored metadata exists #then required task metadata is preserved", async () => {
+    // given
+    const model = { providerID: "openai", modelID: "gpt-5.5" }
+    storeToolMetadata("ses_parent", "call_model", {
+      title: "stored title",
+      metadata: { sessionId: "ses_stored", agent: "oracle", model },
+    })
+
+    const handler = createToolExecuteAfterHandler({
+      ctx: {} as never,
+      hooks: {} as never,
+    })
+
+    const output = {
+      title: "result",
+      output: "original output",
+      metadata: { sessionId: "ses_native", agent: "hephaestus" },
+    }
+
+    // when
+    await handler(
+      { tool: "task", sessionID: "ses_parent", callID: "call_model" },
+      output
+    )
+
+    // then
+    expect(output.title).toBe("stored title")
+    expect(output.metadata).toEqual({ sessionId: "ses_native", agent: "hephaestus", model })
+  })
 })