feat(KB-636): add Missions system for large-scale project planning

- Fix TaskStore sliceId persistence and bidirectional linking between tasks and features
- Add comprehensive mission integration tests for hierarchy, status rollup, and events
- Enhance E2E tests with reorder, cascade delete, and error handling coverage
- Add scheduler integration tests for mission slice activation
- Fix duplicate mission commands in CLI help text
- Add changeset for missions launch

packages/core/src/index.ts

@@ -117,6 +117,8 @@ export type { CentralCoreEvents } from "./central-core.js";
 export { CentralDatabase, createCentralDatabase } from "./central-db.js";
 export type { 
   RegisteredProject, 
+  /** @deprecated Use RegisteredProject instead */
+  ProjectInfo,
   IsolationMode, 
   ProjectStatus, 
   ProjectHealth, 

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

@@ -186,6 +186,45 @@ describe("Mission Integration", () => {
       expect(found).toBeDefined();
       expect(found!.id).toBe(feature.id);
     });
+
+    it("should set task.sliceId when linking feature to task", async () => {
+      const mission = missionStore.createMission({ title: "Test Mission" });
+      const milestone = missionStore.addMilestone(mission.id, { title: "Milestone 1" });
+      const slice = missionStore.addSlice(milestone.id, { title: "Slice 1" });
+      const feature = missionStore.addFeature(slice.id, { title: "Feature 1" });
+
+      const task = await taskStore.createTask({
+        description: "Implement feature",
+        title: "Feature implementation",
+      });
+
+      // Link feature to task
+      missionStore.linkFeatureToTask(feature.id, task.id);
+
+      // Reload task and verify sliceId was set
+      const reloaded = await taskStore.getTask(task.id);
+      expect(reloaded.sliceId).toBe(slice.id);
+    });
+
+    it("should clear task.sliceId when unlinking feature from task", async () => {
+      const mission = missionStore.createMission({ title: "Test Mission" });
+      const milestone = missionStore.addMilestone(mission.id, { title: "Milestone 1" });
+      const slice = missionStore.addSlice(milestone.id, { title: "Slice 1" });
+      const feature = missionStore.addFeature(slice.id, { title: "Feature 1" });
+
+      const task = await taskStore.createTask({
+        description: "Implement feature",
+        title: "Feature implementation",
+      });
+
+      // Link and then unlink
+      missionStore.linkFeatureToTask(feature.id, task.id);
+      missionStore.unlinkFeatureFromTask(feature.id);
+
+      // Reload task and verify sliceId was cleared
+      const reloaded = await taskStore.getTask(task.id);
+      expect(reloaded.sliceId).toBeUndefined();
+    });
   });
 
   describe("Status Rollup", () => {

packages/core/src/mission-store.ts

@@ -919,6 +919,11 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       status: "triaged",
     });
 
+    // Also update the task's sliceId for bidirectional linking
+    this.db.prepare(`
+      UPDATE tasks SET sliceId = ? WHERE id = ?
+    `).run(feature.sliceId, taskId);
+
     this.emit("feature:linked", { feature: updated, taskId });
 
     // Recompute slice status
@@ -941,11 +946,21 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       throw new Error(`Feature ${featureId} not found`);
     }
 
+    // Get the taskId before clearing it
+    const { taskId } = feature;
+
     const updated = this.updateFeature(featureId, {
       taskId: undefined,
       status: "defined",
     });
 
+    // Clear the task's sliceId
+    if (taskId) {
+      this.db.prepare(`
+        UPDATE tasks SET sliceId = NULL WHERE id = ?
+      `).run(taskId);
+    }
+
     // Recompute slice status
     this.recomputeSliceStatus(updated.sliceId);
 

packages/core/src/store.ts

@@ -164,6 +164,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       breakIntoSubtasks: row.breakIntoSubtasks ? true : undefined,
       enabledWorkflowSteps: (() => { const e = fromJson<string[]>(row.enabledWorkflowSteps); return e && e.length > 0 ? e : undefined; })(),
       modifiedFiles: (() => { const m = fromJson<string[]>(row.modifiedFiles); return m && m.length > 0 ? m : undefined; })(),
+      sliceId: row.sliceId || undefined,
     };
   }
 
@@ -179,10 +180,10 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
         summary, thinkingLevel, createdAt, updatedAt, columnMovedAt,
         dependencies, steps, log, attachments,
         comments, workflowStepResults, prInfo, issueInfo, mergeDetails,
-        breakIntoSubtasks, enabledWorkflowSteps, modifiedFiles
+        breakIntoSubtasks, enabledWorkflowSteps, modifiedFiles, sliceId
       ) VALUES (
         ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
-        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
+        ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
       )
     `).run(
       task.id,
@@ -223,6 +224,7 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       task.breakIntoSubtasks ? 1 : 0,
       toJson(task.enabledWorkflowSteps || []),
       toJson(task.modifiedFiles || []),
+      task.sliceId ?? null,
     );
     this.db.bumpLastModified();
   }

packages/core/src/types.ts

@@ -961,6 +961,9 @@ export interface RegisteredProject {
   settings?: ProjectSettings;
 }
 
+/** @deprecated Alias for RegisteredProject - use RegisteredProject instead */
+export type ProjectInfo = RegisteredProject;
+
 /** Health metrics for a registered project */
 export interface ProjectHealth {
   /** Project ID reference */