fix(node): enforce node.invoke timeout in node client

Use the timeout provided on node invoke requests to ensure node
clients always respond with a result.

This prevents gateway-side node.invoke calls from hanging until the
gateway timeout when a node command stalls.

Tests:
- swift test --filter GatewayNodeSessionTests

apps/shared/ClawdbotKit/Tests/ClawdbotKitTests/GatewayNodeSessionTests.swift

@@ -0,0 +1,56 @@
+import Foundation
+import Testing
+@testable import ClawdbotKit
+import ClawdbotProtocol
+
+struct GatewayNodeSessionTests {
+    @Test
+    func invokeWithTimeoutReturnsUnderlyingResponseBeforeTimeout() async {
+        let request = BridgeInvokeRequest(id: "1", command: "x", paramsJSON: nil)
+        let response = await GatewayNodeSession.invokeWithTimeout(
+            request: request,
+            timeoutMs: 50,
+            onInvoke: { req in
+                #expect(req.id == "1")
+                return BridgeInvokeResponse(id: req.id, ok: true, payloadJSON: "{}", error: nil)
+            }
+        )
+
+        #expect(response.ok == true)
+        #expect(response.error == nil)
+        #expect(response.payloadJSON == "{}")
+    }
+
+    @Test
+    func invokeWithTimeoutReturnsTimeoutError() async {
+        let request = BridgeInvokeRequest(id: "abc", command: "x", paramsJSON: nil)
+        let response = await GatewayNodeSession.invokeWithTimeout(
+            request: request,
+            timeoutMs: 10,
+            onInvoke: { _ in
+                try? await Task.sleep(nanoseconds: 200_000_000) // 200ms
+                return BridgeInvokeResponse(id: "abc", ok: true, payloadJSON: "{}", error: nil)
+            }
+        )
+
+        #expect(response.ok == false)
+        #expect(response.error?.code == .unavailable)
+        #expect(response.error?.message.contains("timed out") == true)
+    }
+
+    @Test
+    func invokeWithTimeoutZeroDisablesTimeout() async {
+        let request = BridgeInvokeRequest(id: "1", command: "x", paramsJSON: nil)
+        let response = await GatewayNodeSession.invokeWithTimeout(
+            request: request,
+            timeoutMs: 0,
+            onInvoke: { req in
+                try? await Task.sleep(nanoseconds: 5_000_000)
+                return BridgeInvokeResponse(id: req.id, ok: true, payloadJSON: nil, error: nil)
+            }
+        )
+
+        #expect(response.ok == true)
+        #expect(response.error == nil)
+    }
+}