model : add control vector support where missing (#20653)

* Add control vector functions to qwen3.5 and qwen-next models

* Add missing cvec compatibility to the rest of the models

* Adjust comments and formatting

* cleanup

* whitespace

---------

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

src/models/lfm2.cpp

@@ -177,6 +177,9 @@ llm_build_lfm2<iswa>::llm_build_lfm2(const llama_model & model, const llm_graph_
         cb(ffn_norm_out, "model.layers.{}.ffn_out", il);
 
         cur = ggml_add(ctx0, cur, ffn_out);
+
+        cur = build_cvec(cur, il);
+        cb(cur, "l_out", il);
     }
 
     cur = build_norm(cur, model.output_norm, NULL, LLM_NORM_RMS, -1);