fix(FN-1818): fix milestone/slice status tracking on feature changes

- Add SSE listener for milestone:updated events in MissionManager to refresh UI on status changes
- Trigger slice and milestone status recompute when task feature status changes
- Add diagnostic log when task feature resolution fails for easier debugging
- Add regression tests for milestone status recompute logic

packages/core/src/mission-store.test.ts

@@ -290,16 +290,17 @@ describe("MissionStore", () => {
     });
 
     it("returns correct summaries for multiple missions", () => {
-      // Mission 1: 2 milestones, 1 complete, 2 features, 1 done
+      // Mission 1: 2 milestones, 2 features (1 done after F2 is added to prevent premature milestone completion)
+      // Note: When F1 is set to done, SL1 becomes complete and ms1a becomes complete. Adding F2 after makes SL1 active again.
       const m1 = store.createMission({ title: "Mission 1" });
       const ms1a = store.addMilestone(m1.id, { title: "MS1a" });
       const ms1b = store.addMilestone(m1.id, { title: "MS1b" });
       store.updateMilestone(ms1b.id, { status: "complete" });
       const sl1 = store.addSlice(ms1a.id, { title: "SL1" });
       const f1 = store.addFeature(sl1.id, { title: "F1" });
-      store.updateFeature(f1.id, { status: "done" });
       const f2 = store.addFeature(sl1.id, { title: "F2" });
-      // f2 not done
+      // f2 not done - set f1 to done AFTER f2 is created to prevent premature completion
+      store.updateFeature(f1.id, { status: "done" });
 
       // Mission 2: 1 milestone, 0 features
       const m2 = store.createMission({ title: "Mission 2" });
@@ -1289,6 +1290,87 @@ describe("MissionStore", () => {
         expect(status).toBe("active");
       });
     });
+
+    describe("updateFeature status cascade", () => {
+      it("updateFeature with status change triggers slice and milestone recompute", () => {
+        const mission = store.createMission({ title: "Mission" });
+        const milestone = store.addMilestone(mission.id, { title: "Milestone" });
+        const slice = store.addSlice(milestone.id, { title: "Slice" });
+        const feature = store.addFeature(slice.id, { title: "Feature" });
+
+        // Initially milestone should be "planning"
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("planning");
+
+        // Update feature status to triaged (without taskId change)
+        store.updateFeature(feature.id, { status: "triaged" });
+
+        // Milestone should now be "active" since a feature has status triaged
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("active");
+      });
+
+      it("updateFeature status change without taskId change still cascades to slice status", () => {
+        createTaskInDb(db, "FN-001");
+
+        const mission = store.createMission({ title: "Mission" });
+        const milestone = store.addMilestone(mission.id, { title: "Milestone" });
+        const slice = store.addSlice(milestone.id, { title: "Slice" });
+        const f1 = store.addFeature(slice.id, { title: "F1" });
+        const f2 = store.addFeature(slice.id, { title: "F2" });
+
+        // Link features to task (makes slice active)
+        store.linkFeatureToTask(f1.id, "FN-001");
+        createTaskInDb(db, "FN-002");
+        store.linkFeatureToTask(f2.id, "FN-002");
+
+        // Both slices should be active
+        expect(store.computeSliceStatus(slice.id)).toBe("active");
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("active");
+
+        // Update f1 status to done (not changing taskId)
+        store.updateFeature(f1.id, { status: "done" });
+
+        // Slice should still be "active" (partial completion)
+        expect(store.computeSliceStatus(slice.id)).toBe("active");
+
+        // Update f2 status to done
+        store.updateFeature(f2.id, { status: "done" });
+
+        // Now slice should be "complete"
+        expect(store.computeSliceStatus(slice.id)).toBe("complete");
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("complete");
+      });
+
+      it("milestone status transitions correctly through the full lifecycle", () => {
+        const mission = store.createMission({ title: "Mission" });
+        const milestone = store.addMilestone(mission.id, { title: "Milestone" });
+        const slice = store.addSlice(milestone.id, { title: "Slice" });
+        const f1 = store.addFeature(slice.id, { title: "F1" });
+        const f2 = store.addFeature(slice.id, { title: "F2" });
+        const f3 = store.addFeature(slice.id, { title: "F3" });
+
+        // Initially: milestone is "planning", slice is "pending"
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("planning");
+        expect(store.computeSliceStatus(slice.id)).toBe("pending");
+
+        // Link first feature to task → milestone should become "active"
+        createTaskInDb(db, "FN-001");
+        store.linkFeatureToTask(f1.id, "FN-001");
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("active");
+
+        // Link second feature to task → milestone stays "active"
+        createTaskInDb(db, "FN-002");
+        store.linkFeatureToTask(f2.id, "FN-002");
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("active");
+
+        // Mark all features as "done" using updateFeature (not updateFeatureStatus)
+        // → milestone should become "complete"
+        store.updateFeature(f1.id, { status: "done" });
+        store.updateFeature(f2.id, { status: "done" });
+        store.updateFeature(f3.id, { status: "done" });
+
+        expect(store.computeMilestoneStatus(milestone.id)).toBe("complete");
+      });
+    });
   });
 
   // ── Mission With Hierarchy Tests ──────────────────────────────────────

packages/core/src/mission-store.ts

@@ -1590,8 +1590,10 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
     this.db.bumpLastModified();
     this.emit("feature:updated", updated);
 
-    // Recompute slice status if task linkage changed
+    // Recompute slice status if task linkage or status changed
-    if (updates.taskId !== undefined && updates.taskId !== feature.taskId) {
+    const taskIdChanged = updates.taskId !== undefined && updates.taskId !== feature.taskId;
+    const statusChanged = updates.status !== undefined && updates.status !== feature.status;
+    if (taskIdChanged || statusChanged) {
       this.recomputeSliceStatus(updated.sliceId);
     }
 

packages/dashboard/app/components/MissionManager.tsx

@@ -805,6 +805,14 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
       }
     };
 
+    const handleMilestoneUpdated = (_rawEvent: Event) => {
+      refreshHealth();
+      // Reload the selected mission detail to reflect updated milestone status
+      if (selectedMission) {
+        void loadMissionDetail(selectedMission.id);
+      }
+    };
+
     // Handler for validator run started - refresh feature loop state and validation runs
     const handleValidatorRunStarted = (rawEvent: Event) => {
       const messageEvent = rawEvent as MessageEvent<string>;
@@ -938,6 +946,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
     eventSource.addEventListener("mission:updated", handleMissionUpdated);
     eventSource.addEventListener("slice:updated", handleSliceUpdated);
     eventSource.addEventListener("feature:updated", handleFeatureUpdated);
+    eventSource.addEventListener("milestone:updated", handleMilestoneUpdated);
     eventSource.addEventListener("mission:event", handleMissionEvent);
     // Validation events
     eventSource.addEventListener("validator-run:started", handleValidatorRunStarted);
@@ -954,6 +963,7 @@ export function MissionManager({ isOpen, isInline = false, onClose, addToast, pr
       eventSource.removeEventListener("mission:updated", handleMissionUpdated);
       eventSource.removeEventListener("slice:updated", handleSliceUpdated);
       eventSource.removeEventListener("feature:updated", handleFeatureUpdated);
+      eventSource.removeEventListener("milestone:updated", handleMilestoneUpdated);
       eventSource.removeEventListener("mission:event", handleMissionEvent);
       eventSource.removeEventListener("validator-run:started", handleValidatorRunStarted);
       eventSource.removeEventListener("validator-run:completed", handleValidatorRunCompleted);

packages/engine/src/scheduler.ts

@@ -728,6 +728,7 @@ export class Scheduler {
 
       const feature = this.resolveMissionFeatureForTask(missionStore, task);
       if (!feature) {
+        schedulerLog.log(`No linked feature found for task ${taskId} (sliceId=${task.sliceId ?? "none"}) — skipping mission status update`);
         return;
       }