model: Add support for Nanbeige4.2 (#25994)

* support nanbeige4.2 model

* fix

* fix flake8 Lint check

* fix loop bound check and drop redundant head_dim

---------

Co-authored-by: root <lizongqiang@kanzhun.com>

src/llama-arch.h

@@ -148,6 +148,7 @@ enum llm_arch {
     LLM_ARCH_EAGLE3,
     LLM_ARCH_MINIMAX_M3,
     LLM_ARCH_DFLASH,
+    LLM_ARCH_NANBEIGE,
     LLM_ARCH_UNKNOWN,
 };
 
@@ -226,6 +227,8 @@ enum llm_kv {
     LLM_KV_TOKEN_SHIFT_COUNT,
     LLM_KV_INTERLEAVE_MOE_LAYER_STEP,
     LLM_KV_FULL_ATTENTION_INTERVAL,
+    LLM_KV_NUM_LOOPS,
+    LLM_KV_SKIP_LOOP_FINAL_NORM,
 
     LLM_KV_ATTENTION_HEAD_COUNT,
     LLM_KV_ATTENTION_HEAD_COUNT_KV,