fix: prevent session summary from being cleared on exit

The session stats summary was being displayed momentarily then cleared.
This was caused by drainStdin() re-enabling raw mode AFTER we had already
exited the alternate screen and written the summary.

Changes:
- Remove drainStdin() from normal exit flow - it was interfering with terminal
- Drain pending DECRQM responses BEFORE exiting alternate screen, while still in raw mode
- Add newline after summary to ensure shell prompt appears correctly
- Keep drainStdin() available for signal handlers but don't use it in normal exit

src/commands/components/execute/index.ts

@@ -18,7 +18,6 @@ import { getThinkingMessage } from "@constants/status-messages";
 import {
   enterFullscreen,
   registerExitHandlers,
-  drainStdin,
 } from "@utils/core/terminal";
 import { createCallbacks } from "@commands/chat-tui";
 import { agentLoader } from "@services/agent-loader";
@@ -32,9 +31,8 @@ interface ExecuteContext {
 const createHandleExit = (): (() => void) => (): void => {
   cleanupPermissionHandler();
   // Note: Session stats are displayed by the TUI exit handler in app.tsx
-  // Drain stdin to consume pending terminal responses (e.g. DECRQM 997;1n)
-  // before exiting, so they don't echo as garbage text in the shell
-  drainStdin().then(() => process.exit(0));
+  // The TUI handles terminal cleanup and draining stdin before exit
+  process.exit(0);
 };
 
 const createHandleModelSelect =

src/tui-solid/app.tsx

@@ -579,21 +579,47 @@ export function tui(options: TuiRenderOptions): Promise<TuiOutput> {
 
     const handleExit = (output: TuiOutput): void => {
       try {
-        writeSync(1, TERMINAL_RESET);
-
-        const state = appStore.getState();
-        const summary = generateSessionSummary({
-          sessionId: output.sessionId ?? "unknown",
-          sessionStats: state.sessionStats,
-          modifiedFiles: state.modifiedFiles,
-          modelName: state.model,
-          providerName: state.provider,
-        });
-        writeSync(1, summary);
+        // First, drain any pending terminal responses (e.g. DECRQM 997;1n)
+        // while still in raw mode, before exiting alternate screen
+        const drainTimeout = 50; // 50ms is enough for terminal responses
+        
+        const finishExit = (): void => {
+          writeSync(1, TERMINAL_RESET);
+          
+          const state = appStore.getState();
+          const summary = generateSessionSummary({
+            sessionId: output.sessionId ?? "unknown",
+            sessionStats: state.sessionStats,
+            modifiedFiles: state.modifiedFiles,
+            modelName: state.model,
+            providerName: state.provider,
+          });
+          writeSync(1, summary + "\n");
+          resolve(output);
+        };
+        
+        // If stdin is TTY and in raw mode, try to drain pending data
+        if (process.stdin.isTTY && process.stdin.isRaw) {
+          const sink = (): void => {};
+          process.stdin.on("data", sink);
+          
+          const cleanup = (): void => {
+            process.stdin.removeListener("data", sink);
+            // Read and discard any buffered data
+            while (process.stdin.read() !== null) {
+              // drain
+            }
+            finishExit();
+          };
+          
+          setTimeout(cleanup, drainTimeout);
+        } else {
+          finishExit();
+        }
       } catch {
         // Ignore - stdout may already be closed
+        resolve(output);
       }
-      resolve(output);
     };
 
     render(() => <App {...options} onExit={handleExit} />, {