refactor(client): archivedSessionIds public face becomes a plain array

Public snapshot state stays in the store engine's plain-data vocabulary
(immer drafts reject Sets without the MapSet plugin, which stays off):
manager/service/contract carry readonly SessionId[] in Host order, and
the tree derivations build their own transient Set — the
expandedProjects pattern. Membership-unchanged installs still keep the
array reference for Object.is short-circuits.

packages/client/runtime/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/runtime/README.md
-README.md: 52d2caf51d2fdaf48a06e6d56292fe087568eba5
-README.zh.md: d7e807cd7dffdd81a106488884031fccbb8a6d65
+README.md: 022dc6f82ea7aa1490144449ea61a84a512906a2
+README.zh.md: 4d0f74f573a5e03b05755cfcfea930e69ef386e2

packages/client/runtime/README.md

@@ -10,7 +10,7 @@ Workspace and Session lists have independent monotone `pending` → `ready` base
 
 `WorkspacesService.delete(workspaceId)` removes the registration from the client projection after the successful unary response; the matching `host/workspace-removed` frame is idempotent and synchronizes other tabs. Session state and the current Session selection are independent, so accounted Sessions immediately project under Ungrouped after their Workspace disappears.
 
-`WorkspaceListState.archivedSessionIds` mirrors the Host's registry-global archive set (a `ReadonlySet` replaced only when membership changes). It is full-snapshot state: the `workspace.list` baseline, the `archiveSession` unary echo, and the `host/archived-sessions-changed` frame each install the complete set. `WorkspacesService.archiveSession(sessionId)` archives over the wire; the projection sweep clears the current selection into the New Session view state whenever it lands in the archive set — one rule covering the local echo, another tab's frame, and a reconnect baseline restoring a selection archived while this client was away. A set installed while a `workspace.list` request is in flight also supersedes that stale baseline's set. Grouping surfaces hide members everywhere while the session rows stay in the list store.
+`WorkspaceListState.archivedSessionIds` mirrors the Host's registry-global archive set (a `readonly SessionId[]` in Host order, replaced only when membership changes; consumers needing O(1) lookups build a transient Set). It is full-snapshot state: the `workspace.list` baseline, the `archiveSession` unary echo, and the `host/archived-sessions-changed` frame each install the complete set. `WorkspacesService.archiveSession(sessionId)` archives over the wire; the projection sweep clears the current selection into the New Session view state whenever it lands in the archive set — one rule covering the local echo, another tab's frame, and a reconnect baseline restoring a selection archived while this client was away. A set installed while a `workspace.list` request is in flight also supersedes that stale baseline's set. Grouping surfaces hide members everywhere while the session rows stay in the list store.
 
 SlotsService gives the renderer separate bare observables for `useSessions` and `useWorkspaces`; web-react creates the hooks. Workspace business state does not enter `SessionListState` or an entry store.
 

packages/client/runtime/README.zh.md

@@ -10,7 +10,7 @@ Workspace 和 Session 列表各自具有单调的 `pending` → `ready` 基线
 
 `WorkspacesService.delete(workspaceId)` 在一元响应成功后从客户端投影中移除注册记录；对应的 `host/workspace-removed` 帧具有幂等性，并负责同步其他标签页。Session 状态与当前 Session selection 相互独立，因此 Workspace 消失后，其已纳入客户端投影的 Session 会立即投影到 Ungrouped 下。
 
-`WorkspaceListState.archivedSessionIds` 镜像 Host 的注册表级全局归档集合（一个 `ReadonlySet`，仅在成员变化时才替换）。它是全快照状态：`workspace.list` 基线、`archiveSession` 一元回声和 `host/archived-sessions-changed` 帧各自安装完整集合。`WorkspacesService.archiveSession(sessionId)` 通过 wire 归档；投影层在当前 selection 落入归档集合时统一清空为 New Session 视图状态——一条规则同时覆盖本地回声、其他标签页的帧、以及重连基线恢复出一个离线期间被归档的 selection。在 `workspace.list` 请求进行中安装的集合还会取代该过期基线携带的集合。各分组视图在所有位置隐藏集合成员，而会话行本身仍留在列表 store 中。
+`WorkspaceListState.archivedSessionIds` 镜像 Host 的注册表级全局归档集合（一个按 Host 顺序的 `readonly SessionId[]`，仅在成员变化时才替换；需要 O(1) 查询的消费方自建临时 Set）。它是全快照状态：`workspace.list` 基线、`archiveSession` 一元回声和 `host/archived-sessions-changed` 帧各自安装完整集合。`WorkspacesService.archiveSession(sessionId)` 通过 wire 归档；投影层在当前 selection 落入归档集合时统一清空为 New Session 视图状态——一条规则同时覆盖本地回声、其他标签页的帧、以及重连基线恢复出一个离线期间被归档的 selection。在 `workspace.list` 请求进行中安装的集合还会取代该过期基线携带的集合。各分组视图在所有位置隐藏集合成员，而会话行本身仍留在列表 store 中。
 
 SlotsService 分别为 renderer 提供 `useSessions` 与 `useWorkspaces` 的裸 observable；web-react 创建钩子。Workspace 业务状态不会进入 `SessionListState` 或配置项 store。
 

packages/client/runtime/src/client/workspaces/manager.ts

@@ -14,8 +14,14 @@ export type WorkspaceListPhase = 'pending' | 'ready'
 /** Immutable workspace-list snapshot. */
 export interface WorkspaceListSnapshot {
   items: readonly WorkspaceView[]
-  /** Registry-global archive set (hidden from grouping surfaces; accounting slots retained). */
-  archivedSessionIds: ReadonlySet<SessionId>
+  /**
+   * Registry-global archive set in Host order (hidden from grouping
+   * surfaces; accounting slots retained). A plain array, not a Set: public
+   * snapshot state stays in the store engine's plain-data vocabulary
+   * (immer drafts reject Sets without the MapSet plugin); membership
+   * lookups build their own transient Set where they need one.
+   */
+  archivedSessionIds: readonly SessionId[]
   state: 'idle' | 'loading' | 'error'
   phase: WorkspaceListPhase
   error: RpcError | null
@@ -32,7 +38,7 @@ export class WorkspaceManager {
   private itemViewsCache: readonly WorkspaceView[] = []
   // Full-snapshot state (list response / unary response / changed frame all
   // carry the complete set), so deltas never merge — installs replace.
-  private archivedSessionIds: ReadonlySet<SessionId> = new Set()
+  private archivedSessionIds: readonly SessionId[] = []
   private state: WorkspaceListSnapshot['state'] = 'idle'
   private phase: WorkspaceListPhase = 'pending'
   private error: RpcError | null = null
@@ -230,12 +236,16 @@ export class WorkspaceManager {
     }
   }
 
-  /** Replace the archive set when membership actually changed (set identity backs Object.is short-circuits). */
+  /**
+   * Replace the archive set when membership actually changed (array identity
+   * backs Object.is short-circuits). Host snapshots are append-ordered, so
+   * positional comparison is exact, not merely heuristic.
+   */
   private installArchived(archivedSessionIds: readonly SessionId[]): void {
     if (this.refreshFrames !== null) this.archivedSupersedesRefresh = true
-    if (archivedSessionIds.length === this.archivedSessionIds.size
-      && archivedSessionIds.every(id => this.archivedSessionIds.has(id))) return
-    this.archivedSessionIds = new Set(archivedSessionIds)
+    if (archivedSessionIds.length === this.archivedSessionIds.length
+      && archivedSessionIds.every((id, index) => id === this.archivedSessionIds[index])) return
+    this.archivedSessionIds = [...archivedSessionIds]
     this.notifier.markDirty()
   }
 

packages/client/runtime/src/client/workspaces/service.ts

@@ -15,11 +15,13 @@ import { WorkspaceManager, type WorkspaceListPhase } from './manager.ts'
 export interface WorkspaceListState {
   items: readonly WorkspaceView[]
   /**
-   * Registry-global archive set: grouping surfaces hide these sessions
-   * everywhere (workspace groups and the ungrouped bucket) while their
-   * session logs and workspace accounting slots remain.
+   * Registry-global archive set in Host order: grouping surfaces hide these
+   * sessions everywhere (workspace groups and the ungrouped bucket) while
+   * their session logs and workspace accounting slots remain. A plain array
+   * (store-engine vocabulary; immer drafts reject Sets) — membership lookups
+   * build their own transient Set.
    */
-  archivedSessionIds: ReadonlySet<SessionId>
+  archivedSessionIds: readonly SessionId[]
   state: 'idle' | 'loading' | 'error'
   phase: WorkspaceListPhase
   error: RpcError | null
@@ -64,7 +66,7 @@ export class WorkspacesService implements IWorkspaces {
   constructor(ctx: Context, private readonly api: IApiClient, private readonly sessions: SessionsPort) {
     this.manager = new WorkspaceManager(api)
     this.list = createSnapshotStore<WorkspaceListState>({
-      items: [], archivedSessionIds: new Set(), state: 'idle', phase: 'pending', error: null,
+      items: [], archivedSessionIds: [], state: 'idle', phase: 'pending', error: null,
       baselinesReady: false, recentWorkspaceId: undefined,
     })
     this.manager.subscribe(() => { this.project() })
@@ -101,7 +103,7 @@ export class WorkspacesService implements IWorkspaces {
     for (const id of sessions.ids) {
       const summary = sessions.byId[id]
       if (summary !== undefined && summary.blank && summary.cwd === workspace.path
-        && !archived.has(summary.id)) return summary.id
+        && !archived.includes(summary.id)) return summary.id
     }
     const attempt = this.sessions.create({ workspaceId })
       .finally(() => { this.connecting.delete(workspaceId) })
@@ -317,7 +319,7 @@ export class WorkspacesService implements IWorkspaces {
     // every install path with one rule: the local unary echo, another tab's
     // changed frame, and a reconnect baseline restoring a persisted
     // selection that was archived while this client was away.
-    if (sessions.current !== undefined && workspace.archivedSessionIds.has(sessions.current)) {
+    if (sessions.current !== undefined && workspace.archivedSessionIds.includes(sessions.current)) {
       this.sessions.clear()
     }
     this.list.set({

packages/client/runtime/tests/workspaces-service.spec.ts

@@ -309,13 +309,13 @@ describe('WorkspacesService', () => {
     // Archiving a non-current session installs the unary echo and keeps the selection.
     await expect(workspaces.archiveSession(sid('s-idle'))).resolves.toBeUndefined()
     expect(api.callsOf('workspace.archiveSession')).toEqual([{ sessionId: 's-idle' }])
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-idle'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle'])
     expect(sessions.list.getSnapshot().current).toBe('s-open')
 
     // Archiving the current session clears it into the New Session view state.
     api.onWorkspaceArchiveSession = () => Promise.resolve(ok({ archivedSessionIds: [sid('s-idle'), sid('s-open')] }))
     await workspaces.archiveSession(sid('s-open'))
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-idle', 's-open'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle', 's-open'])
     expect(sessions.list.getSnapshot().current).toBeUndefined()
 
     // A Host failure leaves the set and the selection untouched.
@@ -323,7 +323,7 @@ describe('WorkspacesService', () => {
       code: 'session-not-found', message: 'no session ghost', details: { sessionId: sid('ghost') },
     }))
     await expect(workspaces.archiveSession(sid('ghost'))).rejects.toThrow(/session-not-found/)
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-idle', 's-open'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle', 's-open'])
 
     // The changed frame and the list baseline both re-install the full set.
     workspaces.handleHostEnvelope({
@@ -332,10 +332,10 @@ describe('WorkspacesService', () => {
     } as never)
     // Frame installs ride the notifier's microtask batch before projecting.
     await new Promise(resolve => setTimeout(resolve, 0))
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-idle'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-idle'])
     api.onWorkspaceList = () => Promise.resolve(ok({ items: [], archivedSessionIds: [sid('s-open')] }) as never)
     await workspaces.refresh()
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-open'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-open'])
   })
 
   it('clears a current archived by a remote frame and shields the set from a stale in-flight baseline', async () => {
@@ -363,11 +363,11 @@ describe('WorkspacesService', () => {
     expect(sessions.list.getSnapshot().current).toBeUndefined()
     gate.resolve(ok({ items: [], archivedSessionIds: [] }))
     await hydration
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual(['s-open'])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual(['s-open'])
     // The next (fresh) baseline is authoritative again.
     api.onWorkspaceList = () => Promise.resolve(ok({ items: [], archivedSessionIds: [] }) as never)
     await workspaces.refresh()
-    expect([...workspaces.list.getSnapshot().archivedSessionIds]).toEqual([])
+    expect(workspaces.list.getSnapshot().archivedSessionIds).toEqual([])
   })
 })