server : do not forward --api-key-file to router-spawned child instances (#28938) In router mode, authentication belongs to the router. unset_reserved_args() already unset LLAMA_API_KEY, but did not unset LLAMA_ARG_API_KEY_FILE. When --api-key-file was passed, children re-validated against file keys only, causing clients using --api-key to 401 on chat completions (#28820). In addition, router internal calls without auth headers (such as POST /v1/streams/lookup and DELETE /v1/stream) were silently rejected with 401. Unset LLAMA_ARG_API_KEY_FILE in unset_reserved_args() so no API keys reach child instances.

This keeps keys out of child argv, ensures all keys the router accepts work end-to-end, and prevents router internal stream calls from 401ing. Fixes #28820 Website: Attestations: macOS/iOS: macOS Apple Silicon (arm64) macOS Apple Silicon (arm64, KleidiAI enabled) DISABLED macOS Intel (x64) iOS XCFramework Linux: Ubuntu x64 (CPU) Ubuntu arm64 (CPU) Ubuntu s390x (CPU) Ubuntu x64 (Vulkan) Ubuntu arm64 (Vulkan) Ubuntu x64 (CUDA 12) - CUDA 12.8 libraries Ubuntu x64 (CUDA 13) - CUDA 13.4 libraries Ubuntu arm64 (CUDA 13) - CUDA 13.4 libraries Ubuntu x64 (ROCm 10.0) Ubuntu x64…