feat(KB-635): integrate mission workflows across CLI, extension, and engine

- Add mission CLI commands and pi extension tools for creating missions, milestones, slices, features, and task links
- Extend core mission storage and schema migrations with auto-advance support, task slice linkage, and comment normalization coverage
- Wire mission-aware scheduler and executor behavior so linked features progress with task execution and completed slices can auto-activate follow-on work
- Add regression tests for mission CLI parsing, extension behaviors, scheduler mission semantics, and executor integration

packages/core/src/db.ts

@@ -255,6 +255,7 @@ CREATE TABLE IF NOT EXISTS missions (
   description TEXT,
   status TEXT NOT NULL,
   interviewState TEXT NOT NULL,
+  autoAdvance INTEGER DEFAULT 0,
   createdAt TEXT NOT NULL,
   updatedAt TEXT NOT NULL
 );
@@ -395,6 +396,7 @@ export class Database {
 
     if (version < 5) {
       this.applyMigration(5, () => {
+        this.addColumnIfMissing("missions", "autoAdvance", "INTEGER DEFAULT 0");
         this.migrateLegacyCommentsToUnifiedComments();
       });
     }

packages/core/src/mission-store.ts

@@ -93,6 +93,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       description: row.description || undefined,
       status: row.status as MissionStatus,
       interviewState: row.interviewState as InterviewState,
+      autoAdvance: Boolean(row.autoAdvance),
       createdAt: row.createdAt,
       updatedAt: row.updatedAt,
     };
@@ -169,19 +170,21 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       description: input.description,
       status: "planning",
       interviewState: "not_started",
+      autoAdvance: false,
       createdAt: now,
       updatedAt: now,
     };
 
     this.db.prepare(`
-      INSERT INTO missions (id, title, description, status, interviewState, createdAt, updatedAt)
-      VALUES (?, ?, ?, ?, ?, ?, ?)
+      INSERT INTO missions (id, title, description, status, interviewState, autoAdvance, createdAt, updatedAt)
+      VALUES (?, ?, ?, ?, ?, ?, ?, ?)
     `).run(
       mission.id,
       mission.title,
       mission.description ?? null,
       mission.status,
       mission.interviewState,
+      mission.autoAdvance ? 1 : 0,
       mission.createdAt,
       mission.updatedAt,
     );
@@ -270,6 +273,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
         description = ?,
         status = ?,
         interviewState = ?,
+        autoAdvance = ?,
         updatedAt = ?
       WHERE id = ?
     `).run(
@@ -277,6 +281,7 @@ export class MissionStore extends EventEmitter<MissionStoreEvents> {
       updated.description ?? null,
       updated.status,
       updated.interviewState,
+      updated.autoAdvance ? 1 : 0,
       updated.updatedAt,
       updated.id,
     );