model : add support for Phi4ForCausalLMV (#20168)

* Add support for Phi4ForCausalLMV.

* Fix Phi-4 vision parity (correcting SigLIP2 patch-kernel export layout) and matching HF NaFlex resize behavior in mtmd.

* Rename contants + fix tokenizer label

* Clean-ups.

* Fix GGUF export.

* Set tokenizer.ggml.pre explicitly.

* Default vocab name rather than forcing it.

* Clean-ups.

* Fix indent.

* Fix subscriptable error.

* remov overcomplicated code path

* Clean-ups.

---------

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>

tools/mtmd/models/siglip.cpp

@@ -4,7 +4,7 @@ ggml_cgraph * clip_graph_siglip::build() {
     ggml_tensor * inp = build_inp();
 
     ggml_tensor * learned_pos_embd = model.position_embeddings;
-    if (proj_type == PROJECTOR_TYPE_LFM2) {
+    if (proj_type == PROJECTOR_TYPE_LFM2 || proj_type == PROJECTOR_TYPE_PHI4) {
         learned_pos_embd = resize_position_embeddings();
     }
 
@@ -75,6 +75,14 @@ ggml_cgraph * clip_graph_siglip::build() {
             hparams.ffn_op,
             -1);
 
+    } else if (proj_type == PROJECTOR_TYPE_PHI4) {
+        cur = build_ffn(cur,
+            model.mm_0_w, model.mm_0_b,
+            nullptr, nullptr,
+            model.mm_2_w, model.mm_2_b,
+            FFN_GELU,
+            -1);
+
     } else {
         GGML_ABORT("SigLIP: Unsupported projector type");
     }