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