fix: send stty resize on every resize with hidden command output

Backend:
- Remove _stty_sent guard to send stty on EVERY resize
- Use stty -echo to hide command, then delete the command line with ANSI escapes
- Change log level from info to debug

Frontend:
- Add window resize listener as fallback to ResizeObserver
- 250ms debounce to avoid excessive refits
- Proper cleanup on unmount

apps/web/src/components/terminal.tsx

@@ -284,6 +284,16 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
     });
     resizeObserver.observe(container);
 
+    // Window resize fallback (for viewport changes that don't affect container dimensions)
+    let windowResizeTimeout: ReturnType<typeof setTimeout>;
+    const handleWindowResize = () => {
+      clearTimeout(windowResizeTimeout);
+      windowResizeTimeout = setTimeout(() => {
+        requestAnimationFrame(() => fitTerminal());
+      }, 250);
+    };
+    window.addEventListener("resize", handleWindowResize);
+
     // Refit after mobile header auto-hides (3s delay + 0.3s transition)
     const headerHideTimeout = setTimeout(() => {
       fitTerminal();
@@ -316,8 +326,10 @@ export const TerminalComponent: React.FC<TerminalProps> = ({
 
     return () => {
       clearTimeout(resizeTimeout);
+      clearTimeout(windowResizeTimeout);
       clearTimeout(headerHideTimeout);
       resizeObserver.disconnect();
+      window.removeEventListener("resize", handleWindowResize);
       document.removeEventListener("visibilitychange", handleVisibilityChange);
       if (ws) {
         ws.close();