TextField.Draw re-pushed key.SnippetCmd and key.SelectionCmd every frame
while focused. Re-pushing an unchanged snippet resets the IME's composition
and caret, so commits arriving faster than a frame interleaved with those
resets and desynced the cursor (garbled/duplicated text).
Mirror widget.Editor's updateSnippet/selection gating: track the last-pushed
snippet and caret in the main-owned Renderer (keyed by field ID, reset on
focus (re)gain), and only emit the ops when they actually change. A fresh
push is forced whenever the field (re)gains focus so the IME always starts
from a known state. Also drop a leftover per-frame 'Focused:' debug print.
On-device: rapid back-to-back commits (0.08-0.1s cadence, faster than a
frame) now land cleanly - type HELLO, append+backspace, and a
browser->editor navigation round-trip all produce exact content.
go test -race ./... green.
Greg Pomerantz
46383c1fc1