Rio

- Fixed typing echo in synchronized-output TUIs arriving ~150-200 ms late through Windows ConPTY. ConPTY coalesces output, so a frame's begin/end synchronized-update pair (mode 2026) often arrives inside one chunk; the begin armed Rio's 150 ms timeout but the inline end never disarmed it, so every following frame waited out the timer. An inline end now disarms the timeout, and replaying a buffered update re-arms it when a new begin is still pending (closes [#1753](https://github.com/raphamorim/rio/issues/1753), thanks to @cmoron for the original diagnosis and fix in [#1754](https://github.com/raphamorim/rio/pull/1754), ported to rio-vt by @marc2332 in [#1788](https://github.com/raphamorim/rio/pull/1788), landed via [#1789](https://github.com/raphamorim/rio/pull/1789)).

- rio-vt: synchronized updates whose 150 ms deadline has passed now flush on the next advance() call. Rio's event loop already flushed at the deadline, but embedders that drive the processor straight from a read loop had no timeout driver at all. A client that armed mode 2026 and stalled could freeze their screen until 2 MB of output accumulated. The latency cap now works out of the box for every embedder.