save_hf_pretrained's claimed adapter auto-merge silently exported base
weights; merge explicitly (LoRAMerge -> strip adapters -> unwrap), assert
non-zero adapter B norms and a changed probe weight before writing.
run_gguf_spark2.sh: containerized convert_hf_to_gguf under the same
memory cap + watchdog. Chain verified end-to-end: merged HF export
hash-differs from base on LoRA targets only; Q4_K_S passes the eval gate.
finetune: merge LoRA via streaming HF export (avoids 2x-model save peak)
