claude streams a running 'estimated_tokens' counter as system/thinking_tokens
events — many per turn (thousands in a long turn). renderStream rendered each
as a '⚙ thinking_tokens' note, flooding the terminal scrollback. Coalesce
consecutive ticks into a single '🧠 thinking … ~N tokens' note row that
updates in place; reuse the row only while it's still the last one rendered
(nextElementSibling == null) so any other event starts a fresh one. Closes
#1818.
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