* Handle Cohere2MoE unopened thinking before tools
* Cohere2MoE: route unopened thinking to reasoning_content; test in active target
Follow-up to #1968. Gate extract_reasoning on reasoning_format only (drop the
"&& enable_thinking" addition) so the unopened-thinking handling does not also
change where an opened thinking block is routed. Under --reasoning off
(enable_thinking=false, reasoning_format defaults to DEEPSEEK) an orphaned
thinking block is now quarantined in reasoning_content with clean content and a
native tool call, instead of leaking the thinking prose into the user-facing
answer.
Move the Cohere2MoE end-to-end parser cases into tests/test-chat-auto-parser.cpp,
which CMake actually builds. tests/test-chat.cpp has been disabled in
tests/CMakeLists.txt since #723, so cohere coverage added there never ran in CI;
revert the local band-aids to that file.
* Cohere2MoE: harden parser from NMC eval findings
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Co-authored-by: Joel Farthing <262452229+joelfarthing@users.noreply.github.com>