feat: optimize heartbeat token usage

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/heartbeat-workspace-session.test.ts

@@ -93,16 +93,26 @@ describe("shouldResetTaskSessionForWake", () => {
     expect(shouldResetTaskSessionForWake({ wakeReason: "issue_assigned" })).toBe(true);
   });
 
-  it("resets session context on timer heartbeats", () => {
-    expect(shouldResetTaskSessionForWake({ wakeSource: "timer" })).toBe(true);
+  it("preserves session context on timer heartbeats", () => {
+    expect(shouldResetTaskSessionForWake({ wakeSource: "timer" })).toBe(false);
   });
 
-  it("resets session context on manual on-demand invokes", () => {
+  it("preserves session context on manual on-demand invokes by default", () => {
     expect(
       shouldResetTaskSessionForWake({
         wakeSource: "on_demand",
         wakeTriggerDetail: "manual",
       }),
+    ).toBe(false);
+  });
+
+  it("resets session context when a fresh session is explicitly requested", () => {
+    expect(
+      shouldResetTaskSessionForWake({
+        wakeSource: "on_demand",
+        wakeTriggerDetail: "manual",
+        forceFreshSession: true,
+      }),
     ).toBe(true);
   });