assertCursorKimiK3HistoryReplayable threw for any assistant turn lacking a
non-empty thinking block, including same-model kimi-k3 turns whose stream
carried no thinkingDelta events. Such a turn is persisted with only
text/toolCall blocks, so every subsequent turn failed locally before any
request, permanently bricking the session.
Split the two failure modes: foreign history still hard-errors (another
model's turns cannot replay K3 reasoning), but a same-model turn missing
thinking now degrades to a one-time warning and replays without the
reasoning part via buildCursorAssistantContent, which already omits it.
Fixes#7516
roboomp
467437a47e