fix(session): separate PTY write from screen -X stuff

Regular user input should go through PTY, only respawn controller
should use screen -X stuff. Added writeViaScreen() method for
programmatic input that needs reliable Enter key delivery.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/respawn-controller.ts

@@ -355,7 +355,7 @@ export class RespawnController extends EventEmitter {
     this.stepTimer = setTimeout(() => {
       const prompt = this.config.kickstartPrompt!;
       this.log(`Sending kickstart prompt: "${prompt}"`);
-      this.session.write(prompt + '\r');  // \r triggers key.return in Ink/Claude CLI
+      this.session.writeViaScreen(prompt + '\r');  // \r triggers key.return in Ink/Claude CLI
       this.emit('stepSent', 'kickstart', prompt);
       this.setState('waiting_kickstart');
       this.promptDetected = false;
@@ -418,7 +418,7 @@ export class RespawnController extends EventEmitter {
     this.stepTimer = setTimeout(() => {
       const input = this.config.updatePrompt + '\r\n';  // CRLF for screen + Claude CLI
       this.log(`Sending update prompt: "${this.config.updatePrompt}"`);
-      this.session.write(input);
+      this.session.writeViaScreen(input);
       this.emit('stepSent', 'update', this.config.updatePrompt);
       this.setState('waiting_update');
       this.promptDetected = false;
@@ -432,7 +432,7 @@ export class RespawnController extends EventEmitter {
 
     this.stepTimer = setTimeout(() => {
       this.log('Sending /clear');
-      this.session.write('/clear\r\n');  // CRLF for screen + Claude CLI
+      this.session.writeViaScreen('/clear\r\n');  // CRLF for screen + Claude CLI
       this.emit('stepSent', 'clear', '/clear');
       this.setState('waiting_clear');
       this.promptDetected = false;
@@ -445,7 +445,7 @@ export class RespawnController extends EventEmitter {
 
     this.stepTimer = setTimeout(() => {
       this.log('Sending /init');
-      this.session.write('/init\r\n');  // CRLF for screen + Claude CLI
+      this.session.writeViaScreen('/init\r\n');  // CRLF for screen + Claude CLI
       this.emit('stepSent', 'init', '/init');
       this.setState('waiting_init');
       this.promptDetected = false;

src/session.ts

@@ -898,23 +898,26 @@ export class Session extends EventEmitter {
   }
 
   // Send input to the PTY (for interactive sessions)
-  // When using screen, prefers screen -X stuff for reliable input delivery
   write(data: string): void {
-    // Try screen -X stuff first if we have a screen session
-    // This is more reliable for sending Enter key to Claude CLI
-    if (this._screenManager && this._screenSession) {
-      const success = this._screenManager.sendInput(this.id, data);
-      if (success) {
-        return;
-      }
-      // Fall through to PTY write if screen command failed
-    }
-
     if (this.ptyProcess) {
       this.ptyProcess.write(data);
     }
   }
 
+  // Send input via screen -X stuff (for programmatic input like respawn controller)
+  // This bypasses PTY and sends directly to screen, more reliable for Enter key
+  writeViaScreen(data: string): boolean {
+    if (this._screenManager && this._screenSession) {
+      return this._screenManager.sendInput(this.id, data);
+    }
+    // Fallback to PTY write
+    if (this.ptyProcess) {
+      this.ptyProcess.write(data);
+      return true;
+    }
+    return false;
+  }
+
   // Resize the PTY
   resize(cols: number, rows: number): void {
     if (this.ptyProcess) {