fix(tui): bound input event draining

handle_input() previously drained terminal events in an unbounded
while-poll loop, so a continuously-ready input stream could keep the
frontend inside handle_input() indefinitely, starving managed-event
processing, completion checks, peer-close stop policy, and rendering
in the outer run_tui() loop.

Bound each call to at most INPUT_EVENT_WORK_BUDGET (128) polled
terminal events, mirroring the MANAGED_EVENT_WORK_BUDGET pattern
already used for managed event draining. All polled events count
against the budget, including ignored/unknown/release events, so a
stream of non-actionable input can't bypass the bound. Remaining
events are left queued for the next outer-loop iteration rather than
dropped. Quit/Ctrl-C now also breaks out of the drain immediately
after being handled, since there is no benefit to consuming further
buffered input before the outer loop can request managed shutdown.

crates/irtt-cli/src/cmd/tui/run.rs

@@ -26,6 +26,7 @@ use irtt_client::managed::{
 const RENDER_INTERVAL: Duration = Duration::from_millis(250);
 const TUI_WAIT_SLICE: Duration = Duration::from_millis(20);
 const MANAGED_EVENT_CAPACITY: usize = 16_384;
+const INPUT_EVENT_WORK_BUDGET: usize = 128;
 
 pub fn run_tui(
     args: TuiArgs,
@@ -216,7 +217,10 @@ fn drain_final_tui_events(
 }
 fn handle_input(state: &mut TuiState, shutdown_requested: &AtomicBool) -> io::Result<bool> {
     let mut force_render = false;
-    while event::poll(Duration::ZERO)? {
+    for _ in 0..INPUT_EVENT_WORK_BUDGET {
+        if !event::poll(Duration::ZERO)? {
+            break;
+        }
         let Event::Key(key) = event::read()? else {
             continue;
         };
@@ -231,6 +235,7 @@ fn handle_input(state: &mut TuiState, shutdown_requested: &AtomicBool) -> io::Re
                 state.quit_requested = true;
                 shutdown_requested.store(true, Ordering::Relaxed);
                 force_render = true;
+                break;
             }
             KeyCode::Char('r') => {
                 state.clear_visible_history();