* fix(providers): honor Extra API Keys rotation in OpencodeExecutor
OpencodeExecutor.buildHeaders bypassed resolveEffectiveKey, so extraApiKeys
never rotated and an empty primary with populated extras sent no auth header.
Closes#8467
* fix(executors): gate the Authorization header write on the resolved effective key
Co-authored-by: diegosouzapw <8016841+diegosouzapw@users.noreply.github.com>
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Co-authored-by: diegosouzapw <8016841+diegosouzapw@users.noreply.github.com>
