Review follow-up: the bounded echo probe folded at most len(text)*3 raw characters, so a compact-equivalent suffix whose raw span was stretched by interior whitespace was missed - the echo strip was dropped and the interim text was duplicated in the restored transcript. The same retired window existed in the reverse helper (_strip_compact_echo_suffix), pinned by its own test.
Both now share _find_compact_echo_suffix_start: a backward walk over value/suffix that skips whitespace in value, inspects only the echo span, and allocates nothing. It restores the previous output semantics (origin/master folded the whole reasoning text) and is cheaper than the windowed version (no per-call tail fold).
Tests: new journal-reconstruction regression (a 5000-space-stretched echo must appear exactly once; genuine interim text must not be treated as an echo), the suffix-helper oracle updated to window-free semantics, and the window-contract test now pins that a stretched echo IS stripped.
