fix(web): hide verified cold blank sessions

packages/host/apiproxy/src/api/index.ts

@@ -45,7 +45,7 @@ export interface ApiProxy {
 export type {
   HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
   ModelReasoningEffort, ModelSelection, PromptContentPart, QueueAction, SessionModels,
-  SessionProjectionsBlock, SessionSearchItem, SessionsApi, SessionSummary,
+  SessionListMetadata, SessionProjectionsBlock, SessionSearchItem, SessionsApi, SessionSummary,
 } from './sessions.ts'
 export type { DirectoryEntry, DirectoryListing, HostApi } from './host.ts'
 export type {

packages/host/apiproxy/src/api/sessions.schema.ts

@@ -12,7 +12,7 @@ import type { RequestPayload, ResponseValue } from './rpc-map.ts'
 import type { Wire } from './rpc.schema.ts'
 import type {
   HistoryEntry, ModelCatalogFailure, ModelCatalogModel, ModelProviderGroup, ModelReasoning,
-  ModelReasoningEffort, ModelSelection, SessionProjectionsBlock, SessionSearchItem, SessionSummary,
+  ModelReasoningEffort, ModelSelection, SessionListMetadata, SessionProjectionsBlock, SessionSearchItem, SessionSummary,
 } from './sessions.ts'
 import type { ToolEventView } from './events.ts'
 import type { AttachmentIdType, ImageAttachmentLimits, ImageAttachmentRef } from '@deepseek-ai/dsh-attachment'
@@ -215,6 +215,12 @@ export const sessionProjectionsBlockSchema = z.object({
   values: z.record(z.string(), z.unknown()),
 }) as unknown as z.ZodType<Wire<SessionProjectionsBlock>>
 
+/** Host-side validation for the persisted Session-list projection. */
+export const sessionListMetadataProjectionSchema: z.ZodType<SessionListMetadata> = z.object({
+  blank: z.boolean(),
+  lastPromptAt: z.number().nullable(),
+})
+
 /**
  * imageLimits projection unit schema (host-side view validation). zod widens
  * `readonly ImageMediaType[]` to `string[]`; on the JSON wire the two

packages/host/apiproxy/src/api/sessions.ts

@@ -17,6 +17,13 @@ import type { WorkspaceId } from './workspace.ts'
 
 declare module '@deepseek-ai/dsh-session-projection/types' {
   interface SessionProjectionMap {
+    /**
+     * Session-list hints persisted by the projection cache. `blank: false`
+     * is monotonic and may suppress a cold-log probe; `blank: true` is only a
+     * checkpoint-prefix fact and must not hide a cold Session without direct
+     * verification. `lastPromptAt` is the latest human-authored prompt time.
+     */
+    sessionListMetadata: SessionListMetadata
     /**
      * The deployment's image-intake limits: the attachments service's config
      * as this proxy enforces it at prompt admission, constant per host boot.
@@ -28,6 +35,14 @@ declare module '@deepseek-ai/dsh-session-projection/types' {
   }
 }
 
+/** Persisted hints used to summarize a cold Session without reading a large log. */
+export interface SessionListMetadata {
+  /** Whether the checkpoint prefix contains no turn/start event. */
+  blank: boolean
+  /** Latest source.kind=user message time in the checkpoint prefix. */
+  lastPromptAt: number | null
+}
+
 declare module '@deepseek-ai/dsh-llm' {
   interface MessageSourceMap {
     /**