test(server): stub workspace activity dependencies

Give generic session schedule fixtures an explicit empty heartbeat activity result and declare both activity dependencies in the git-watch fixture. This preserves strict stubs while covering the workspace descriptor inputs introduced by heartbeat projection.

packages/server/src/server/session.workspace-git-watch.test.ts

@@ -200,6 +200,7 @@ function createSessionForWorkspaceGitWatchTests(options?: {
     agentManager: createStub<SessionOptions["agentManager"]>({
       subscribe: () => () => {},
       listAgents: () => [],
+      listProviderSubagentActivity: () => [],
       getAgent: () => null,
     }),
     agentStorage: createStub<SessionOptions["agentStorage"]>({
@@ -259,6 +260,9 @@ function createSessionForWorkspaceGitWatchTests(options?: {
       dispose: () => {},
     }),
     workspaceGitService,
+    scheduleService: createStub<SessionOptions["scheduleService"]>({
+      listActiveHeartbeatActivity: async () => [],
+    }),
     mcpBaseUrl: null,
     stt: null,
     tts: null,

packages/server/src/server/session.workspace-resolution-invariants.test.ts

@@ -160,7 +160,9 @@ function createHarness(input: {
     }),
     filesystem: { isDirectory: async () => true },
     chatService: createStub<SessionOptions["chatService"]>({}),
-    scheduleService: createStub<SessionOptions["scheduleService"]>({}),
+    scheduleService: createStub<SessionOptions["scheduleService"]>({
+      listActiveHeartbeatActivity: async () => [],
+    }),
     loopService: createStub<SessionOptions["loopService"]>({}),
     checkoutDiffManager: createStub<SessionOptions["checkoutDiffManager"]>({
       subscribe: async () => ({

packages/server/src/server/test-utils/session-stubs.ts

@@ -55,7 +55,9 @@ export function asChatService(): SessionOptions["chatService"] {
 }
 
 export function asScheduleService(): SessionOptions["scheduleService"] {
-  return createStub<SessionOptions["scheduleService"]>({});
+  return createStub<SessionOptions["scheduleService"]>({
+    listActiveHeartbeatActivity: async () => [],
+  });
 }
 
 export function asLoopService(): SessionOptions["loopService"] {