feat: support scoped Smart Heartbeat plans

Smart Heartbeat plans were implicitly bound to one active project and duplicated across multiple configuration surfaces. Plans can now target Global or selected projects from one authoritative editor, aggregate bounded input across that scope, validate project-specific outputs, and preserve existing data through the schema migration.

Reports remain unscoped with frozen scope metadata, while duplicate Heartbeat forms are removed from Settings and Task Center.

Release note: 智能心跳计划现在可从统一入口选择 Global 或一个、多个 Project；旧配置和历史会自动保留，项目级记忆与后续任务会严格写入所选范围。

src/main/assistant/heartbeat-database.test.ts

@@ -30,6 +30,7 @@ async function createDatabase(): Promise<{
 }
 
 const input = {
+  scope: { kind: 'global' as const },
   name: 'Daily heartbeat',
   timezone: 'UTC',
   recurrence: { type: 'daily' as const, localTime: '18:00' },
@@ -37,6 +38,7 @@ const input = {
   lookbackHours: 24,
   retentionDays: 7
 }
+const now = new Date('2026-08-01T12:00:00.000Z')
 
 const summary = {
   summary: 'A durable summary',
@@ -100,8 +102,105 @@ describe('AssistantDatabase heartbeat persistence', () => {
     ).count
     check.close()
     migrated.close()
-    expect(version).toBe(20)
-    expect(heartbeatTableCount).toBe(3)
+    expect(version).toBe(21)
+    expect(heartbeatTableCount).toBe(4)
+  })
+
+  it('migrates a legacy single-project heartbeat into explicit scope', async () => {
+    const { database, path } = await createDatabase()
+    const project = database.listProjects()[0]!
+    const config = database.createHeartbeatConfig(input)
+    database.close()
+
+    const raw = new DatabaseSync(path)
+    raw
+      .prepare(
+        `UPDATE heartbeat_configs
+         SET project_id = ?, scope_kind = 'global'
+         WHERE id = ?`
+      )
+      .run(project.id, config.id)
+    raw
+      .prepare(
+        'DELETE FROM heartbeat_config_projects WHERE config_id = ?'
+      )
+      .run(config.id)
+    raw.exec('PRAGMA user_version = 20')
+    raw.close()
+
+    const migrated = new AssistantDatabase(path)
+    migrated.initialize('C:\\Workspace')
+    expect(migrated.getHeartbeatConfig(config.id).scope).toEqual({
+      kind: 'projects',
+      projectIds: [project.id]
+    })
+    migrated.close()
+  })
+
+  it('builds one bounded snapshot across only the selected projects', async () => {
+    const { database } = await createDatabase()
+    const first = database.listProjects()[0]!
+    const second = database.createProject({
+      name: 'Second',
+      description: '',
+      rootPath: 'C:\\Second',
+      defaultWorkMode: 'ask'
+    })
+    const excluded = database.createProject({
+      name: 'Excluded',
+      description: '',
+      rootPath: 'C:\\Excluded',
+      defaultWorkMode: 'ask'
+    })
+    database.replaceConversations(
+      [first, second, excluded].map((project, index) => ({
+        id: `00000000-0000-4000-8000-00000000040${index}`,
+        projectId: project.id,
+        title: project.name,
+        updatedAt: now.getTime(),
+        messages: []
+      }))
+    )
+    for (const project of [first, second, excluded]) {
+      database.createTask({
+        id: `task-${project.id}`,
+        projectId: project.id,
+        title: project.name,
+        instructions: '',
+        workMode: 'ask'
+      })
+      database.createMemory({
+        scope: 'project',
+        scopeId: project.id,
+        type: 'fact',
+        content: `${project.name} memory`
+      })
+    }
+    const config = database.createHeartbeatConfig({
+      ...input,
+      scope: {
+        kind: 'projects',
+        projectIds: [first.id, second.id]
+      }
+    })
+
+    const snapshot = database.buildHeartbeatInput(config, now)
+
+    expect(snapshot.scope).toEqual(config.scope)
+    expect(
+      new Set(snapshot.conversations.map((item) => item.projectId))
+    ).toEqual(new Set([first.id, second.id]))
+    expect(
+      new Set(snapshot.tasks.map((item) => item.projectId))
+    ).toEqual(new Set([first.id, second.id]))
+    expect(
+      new Set(
+        snapshot.confirmedMemories
+          .map((item) => item.projectId)
+          .filter(Boolean)
+      )
+    ).toEqual(new Set([first.id, second.id]))
+    database.close()
   })
 
   it('claims one scheduled run durably and advances local recurrence', async () => {
@@ -227,7 +326,10 @@ describe('AssistantDatabase heartbeat persistence', () => {
     const { database } = await createDatabase()
     const project = database.listProjects()[0]!
     const config = database.createHeartbeatConfig(
-      { ...input, projectId: project.id },
+      {
+        ...input,
+        scope: { kind: 'projects', projectIds: [project.id] }
+      },
       new Date('2026-08-01T12:00:00.000Z')
     )
     const claim = database.claimHeartbeatNow(