model: Add EXAONE 4.5 implementations (#21733)

* Add EXAONE 4.5 and Add GQA for MMproj

* mtmd: EXAONE 4.5 vision markers and projector path

EXAONE 4.5 uses <vision> and </vision> for image boundaries; Qwen keeps
<|vision_start|> and <|vision_end|>.

Route EXAONE 4.5 through the Qwen2.5-VL-style encode path (window attention
pattern, optional mmproj input norm). Update exaone4_5 projector weights and
convert_hf_to_gguf for mmproj export.

* mtmd: load EXAONE4 nextn tensors correctly

Align EXAONE4 tensor registration with EXAONE_MOE for NextN/MTP slots and avoid skip-flag propagation on duplicated rope_freqs so model loading succeeds for EXAONE 4.5 GGUF.

* Minor fixes

* Address PR feedback

* Address PR feedback

* Fix EXAONE after merge

* Fix EXAONE 4.5 conversion

* Address PR feedback

* Refactor EXAONE 4.5 conversion

* Address PR feedback

* Fix unintended deletion

* Minor fix

---------

Co-authored-by: LG-AI-EXAONE <exaonemodels@lgresearch.ai>

tools/mtmd/clip-impl.h

@@ -347,6 +347,7 @@ enum projector_type {
     PROJECTOR_TYPE_KIMIK25,
     PROJECTOR_TYPE_NEMOTRON_V2_VL,
     PROJECTOR_TYPE_HUNYUANVL,
+    PROJECTOR_TYPE_EXAONE4_5,
     PROJECTOR_TYPE_MINICPMV4_6,
     PROJECTOR_TYPE_GRANITE_SPEECH,
     PROJECTOR_TYPE_MIMOVL,
@@ -396,6 +397,7 @@ static std::map<projector_type, std::string> PROJECTOR_TYPE_NAMES = {
     { PROJECTOR_TYPE_YASA2,     "yasa2"},
     { PROJECTOR_TYPE_KIMIK25,   "kimik25"},
     { PROJECTOR_TYPE_NEMOTRON_V2_VL, "nemotron_v2_vl"},
+    { PROJECTOR_TYPE_EXAONE4_5, "exaone4_5"},
     { PROJECTOR_TYPE_HUNYUANVL,  "hunyuanvl"},
     { PROJECTOR_TYPE_MINICPMV4_6, "minicpmv4_6"},
     { PROJECTOR_TYPE_GRANITE_SPEECH, "granite_speech"},