fix(codex): preserve transcript sync across mode switches

cli/src/codex/codexLocalLauncher.ts

@@ -46,6 +46,7 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
     let pendingScannerSetup: Promise<void> | null = null;
     let transcriptLocator: CodexTranscriptLocator | null = null;
     let scannerTranscriptPath: string | null = null;
+    let scannerReplayedExistingHistory = false;
     const pendingPlansByTurnId = new Map<string, ProposedPlanMessage>();
     const pendingExecWrappers = new Map<string, PendingExecWrapper>();
     const toolHookBridge = new CodexToolHookBridge();
@@ -76,6 +77,21 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
         });
     };
 
+    const drainAndCleanupScanner = async (
+        activeScanner: CodexSessionScanner,
+        replayedExistingHistory: boolean
+    ): Promise<void> => {
+        try {
+            // Codex can flush its final transcript records after the last watcher tick.
+            await activeScanner.flush();
+            if (replayedExistingHistory) {
+                session.markTranscriptHistoryReplayConsumed();
+            }
+        } finally {
+            await activeScanner.cleanup();
+        }
+    };
+
     const handleSessionFound = (sessionId: string, allowSwitch = false): void => {
         if (primarySessionId && primarySessionId !== sessionId && !allowSwitch) {
             logger.debug(`[codex-local]: Ignoring non-primary Codex session id ${sessionId}; primary is ${primarySessionId}`);
@@ -174,10 +190,11 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
             scannerTranscriptPath = transcriptPath;
             return;
         }
+        const replayExistingHistory = session.shouldReplayTranscriptHistory();
         const createdScanner = await createCodexSessionScanner({
             transcriptPath,
             // 中文注释：导入模式下允许 scanner 首次回放 transcript 全量内容，补齐 Codex 客户端里已有但 Hapi 还未看到的消息。
-            replayExistingHistory: session.replayTranscriptHistoryOnStart,
+            replayExistingHistory,
             onSessionId: (sessionId) => {
                 if (!isPrimarySessionId(sessionId)) {
                     logger.debug(`[codex-local]: Ignoring transcript session id ${sessionId}; primary is ${primarySessionId}`);
@@ -237,11 +254,12 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
             }
         });
         if (shuttingDown) {
-            await createdScanner.cleanup();
+            await drainAndCleanupScanner(createdScanner, replayExistingHistory);
             return;
         }
         scanner = createdScanner;
         scannerTranscriptPath = transcriptPath;
+        scannerReplayedExistingHistory = replayExistingHistory;
     };
 
     const handleTranscriptPath = (transcriptPath: string): Promise<void> => {
@@ -376,7 +394,7 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
         }
         const activeScanner = scanner as CodexSessionScanner | null;
         if (activeScanner) {
-            await activeScanner.cleanup();
+            await drainAndCleanupScanner(activeScanner, scannerReplayedExistingHistory);
         }
         flushAllPendingExecWrappers();
         for (const message of toolHookBridge.finish()) {