User-facing symptom: On terminals that deliver pastes as rapid
KeyCode::Char/Enter streams (notably Windows), paste-burst transient
state
can leak into the next input. Users can see Enter insert a newline when
they meant to submit, or see characters appear late / handled through
the
wrong path.
System problem: PasteBurst is time-based. Clearing only the
classification window (e.g. via clear_window_after_non_char()) can erase
last_plain_char_time without emitting buffered text. If a buffer is
still
non-empty after that, flush_if_due() no longer has a timeout clock to
flush against, so the buffer can get "stuck" until another plain char
arrives.
This was surfaced while adding deterministic regression tests for
paste-burst behavior.
Fix: when disabling burst detection, defuse any in-flight burst state:
flush held/buffered text through handle_paste() (so it follows normal
paste integration), then clear timing and Enter suppression.
Document the rationale inline and update docs/tui-chat-composer.md so
"disable_paste_burst" matches the actual behavior.
Add a narrative doc and inline rustdoc explaining how `ChatComposer`
and `PasteBurst` compose into a single state machine on terminals that
lack reliable bracketed paste (notably Windows).
This documents the key states, invariants, and integration points
(`handle_input_basic`, `handle_non_ascii_char`, tick-driven flush) so
future changes are easier to reason about.
