UPSTREAM PR #17991: arg: fix server router mode not accepting negated arg

[loci-dev]

Mirrored from ggml-org/llama.cpp#17991

Missed a spot at the common_params_to_map used by router mode of server

Note: I'm also changing the overload common_params_parse to common_params_to_map to make it less confusing

Tested and working with llama-server --no-mmap

[loci-review]

Explore the complete analysis inside the Version Insights

Based on my analysis of PR #549 and the performance data, this pull request falls under Condition 1 (no meaningful performance changes).

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Summary

PR #549 fixes argument parsing for negated arguments (e.g., --no-mmap) in server router mode by adding opt.args_neg to the argument-to-options mapping in common_params_to_map. The function was also renamed from common_params_parse for clarity. Performance analysis shows no impact: core inference functions (llama_decode, llama_encode, llama_tokenize) remain unchanged with 0 ns difference in throughput and response time. Power consumption is stable across all binaries. This is a correctness fix with no performance implications.