model : add HunyuanOCR support (#21395)

* HunyuanOCR: add support for text and vision models

- Add HunyuanOCR vision projector (perceiver-based) with Conv2d merge
- Add separate HUNYUAN_OCR chat template (content-before-role format)
- Handle HunyuanOCR's invalid pad_token_id=-1 in converter
- Fix EOS/EOT token IDs from generation_config.json
- Support xdrope RoPE scaling type
- Add tensor mappings for perceiver projector (mm.before_rms, mm.after_rms, etc.)
- Register HunYuanVLForConditionalGeneration for both text and mmproj conversion

* fix proper mapping

* Update gguf-py/gguf/tensor_mapping.py

Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>

* Update tools/mtmd/clip.cpp

Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>

* address comments

* update

* Fix typecheck

* Update convert_hf_to_gguf.py

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* Update convert_hf_to_gguf.py

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* Update convert_hf_to_gguf.py

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* Update convert_hf_to_gguf.py

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

---------

Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>
Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

tools/mtmd/clip-model.h

@@ -358,7 +358,8 @@ struct clip_model {
     // MINICPMV projection
     ggml_tensor * mm_model_pos_embed_k = nullptr;
     ggml_tensor * mm_model_query = nullptr;
-    ggml_tensor * mm_model_proj = nullptr;
+    ggml_tensor * mm_model_proj   = nullptr;
+    ggml_tensor * mm_model_proj_b = nullptr;
     ggml_tensor * mm_model_kv_proj = nullptr;
     ggml_tensor * mm_model_attn_q_w = nullptr;
     ggml_tensor * mm_model_attn_q_b = nullptr;
@@ -419,6 +420,11 @@ struct clip_model {
     ggml_tensor * mm_boi = nullptr;
     ggml_tensor * mm_eoi = nullptr;
 
+    // hunyuanocr perceiver
+    ggml_tensor * mm_pre_norm_w  = nullptr;
+    ggml_tensor * mm_img_begin   = nullptr;
+    ggml_tensor * mm_img_end     = nullptr;
+
     // deepseek ocr sam
     ggml_tensor * patch_embed_proj_w = nullptr;
     ggml_tensor * patch_embed_proj_b = nullptr;