Preload Qwen3.6-27B and Qwen3.6-35B-A3B at startup (load-on-startup)
so both are warm immediately under --models-max 2, set parallel = 1
as the [*] fallback for any other model, and adjust per-model context
size and draft depth.
Replace the per-model llama-server units with a single service that
uses llama-server's --models-preset (models.ini) and --models-max 2,
so the 35B-A3B and 27B models are loaded on demand from one config.
Drop the now-redundant 27B / 27B-MTP / coder-next variant files and
the unused CacheDirectory + slot-save-path KV-slot handling.
