fix(tui): search session references by title

packages/ui/tui/tests/snapshots/session-title-autocomplete.expected.txt

@@ -0,0 +1,24 @@
+terminal 96x36 buffer=normal length=36 base=0 viewport=0
+lifecycle started=1 stopped=0 progress=inactive
+title "DSH snapshot"
+cursor hidden column=8 viewportRow=4 bufferRow=4
+viewport
+0| " DEEPSEEK HARNESS"
+  style 1-8 fg=bright-blue bold
+  style 10-16 bold
+1| " Snapshot agent ready."
+  style 1-21 fg=bright-black
+2| " deepseek-v4-flash  •  main-session"
+  style 1-34 dim
+3| "────────────────────────────────────────────────────────────────────────────────────────────────"
+  style 0-95 dim
+4| " @design                                                                                        "
+  style 8-8 inverse
+5| "────────────────────────────────────────────────────────────────────────────────────────────────"
+  style 0-95 dim
+6| " → Session · Searchable design re  opaque-source-id · /workspace/project · 1970-01-01T00:00:0   "
+  style 1-32 fg=bright-blue
+7| "deepseek-v4-flash  /workspace/project  ↑0 ↓0                         0% context  tools:collapsed"
+  style 0-43 dim
+  style 69-95 dim
+8-35| <blank>

packages/ui/tui/tests/tui.snapshot.ts

@@ -8,6 +8,7 @@ import { agentEvents } from '@deepseek-ai/dsh-agent'
 import { CallId, ReasoningEffortId, type ContentBlock } from '@deepseek-ai/dsh-llm'
 import type {} from '@deepseek-ai/dsh-llm-retry'
 import { SessionId, type JsonValue, type Session } from '@deepseek-ai/dsh-session'
+import SessionReferenceService from '@deepseek-ai/dsh-session-reference'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry, { type ToolDefinition, type ToolResultView } from '@deepseek-ai/dsh-tools'
 import * as ToolCordis from '@deepseek-ai/dsh-tool-cordis'
@@ -21,6 +22,7 @@ import {
   type TuiHarnessOptions,
 } from './harness.ts'
 import { HeadlessTerminal, type TerminalSnapshotOptions } from './headless-terminal.ts'
+import { TestSessionQueryService } from './session-query.ts'
 
 const SNAPSHOTS_DIR = join(dirname(fileURLToPath(import.meta.url)), 'snapshots')
 const REFRESHING = process.env.DSH_SNAPSHOT === 'refresh'
@@ -33,6 +35,7 @@ const CHECKPOINTS = [
   'retry-exhausted',
   'banner-gradient',
   'file-autocomplete',
+  'session-title-autocomplete',
   'code-mode-pending',
   'dynamic-workflow-pending',
   'cordis-tools-pending',
@@ -370,6 +373,30 @@ describe('TUI terminal-state snapshots', () => {
     }
   })
 
+  it('pins session autocomplete discovered through a log-backed title', async () => {
+    const harness = await setupSnapshot({
+      async configureContext(ctx) {
+        ctx.provide('tools', { get: () => undefined } as never)
+        await ctx.plugin(TestSessionQueryService)
+        await ctx.plugin(SessionReferenceService)
+        const source = ctx.sessions.create(SessionId('opaque-source-id'), {
+          meta: { cwd: '/workspace/project', createdAt: 1 },
+        })
+        source.append('session/title', {
+          title: 'Searchable design review',
+          messageSeqs: [],
+          source: { kind: 'fallback' },
+        })
+      },
+    })
+    harness.terminal.send('@design')
+    await vi.waitFor(async () => {
+      expect(await harness.terminal.snapshot()).toContain('Session · Searchable design re')
+    })
+    await checkpoint('session-title-autocomplete', harness.terminal)
+    await disposeSnapshot(harness)
+  })
+
   it('pins Code Mode run_code with its production presenter', async () => {
     const harness = await setupSnapshot({ configureContext: configureAdvancedTools })
     const call = {

packages/ui/tui/tests/tui.spec.ts

@@ -1834,21 +1834,50 @@ describe('pi-tui chat lifecycle and transcript', () => {
   })
 
   it('combines session autocomplete with files and prepares send/steer references asynchronously', async () => {
-    let sourceId = SessionId('uninitialized')
+    const sourceId = SessionId('source-session')
+    const sourceHeader: SessionHeader = {
+      version: 0,
+      id: sourceId,
+      cwd: '/workspace',
+      createdAt: 1,
+    }
+    const noCwdHeader: SessionHeader = {
+      version: 0,
+      id: SessionId('no-cwd'),
+      createdAt: 2,
+    }
+    const sourceEvents: SessionEvent[] = [
+      {
+        type: 'user/message',
+        seq: 0,
+        time: 1,
+        data: { content: [{ type: 'text', text: 'source background' }], source: { kind: 'user' } },
+        surfaceOp: 'append',
+      },
+      {
+        type: 'session/title',
+        seq: 1,
+        time: 2,
+        data: {
+          title: 'Source chat',
+          messageSeqs: [0],
+          source: { kind: 'fallback' },
+        },
+      },
+    ]
     const result = await setup({
+      sessionPersistence: {
+        list: async () => [noCwdHeader, sourceHeader],
+        load: async (id) => {
+          if (id === sourceId) return { meta: sourceHeader, events: sourceEvents }
+          if (id === noCwdHeader.id) return { meta: noCwdHeader, events: [] }
+          throw new Error(`unexpected persisted session ${id}`)
+        },
+      },
       async configureContext(ctx) {
         ctx.provide('tools', { get: () => undefined } as never)
         await ctx.plugin(TestSessionQueryService)
         await ctx.plugin(SessionReferenceService)
-        const source = ctx.sessions.create(SessionId('source-session'), { meta: { cwd: process.cwd(), createdAt: 1 } })
-        sourceId = source.id
-        appendUser(source, 'source background')
-        source.append('session/title', {
-          title: 'Source chat',
-          messageSeqs: [0],
-          source: { kind: 'fallback' },
-        })
-        ctx.sessions.create(SessionId('no-cwd'), { meta: { createdAt: 2 } })
       },
     })
 
@@ -1857,7 +1886,7 @@ describe('pi-tui chat lifecycle and transcript', () => {
     expect(result.terminal.output).toContain('(no cwd)')
     result.terminal.send('\x03')
 
-    result.terminal.send('@source-session')
+    result.terminal.send('@chat')
     await vi.waitFor(() => { expect(result.terminal.output).toContain('Session · Source chat') })
     expect(result.terminal.output).toContain('source-session')
     result.terminal.send('\t')