Add context tracking

internal/llm/llm.go

@@ -249,10 +249,19 @@ func (m *Message) UnmarshalJSON(data []byte) error {
 
 // Model represents an available model from the API.
 type Model struct {
-	ID      string `json:"id"`
-	Created int64  `json:"created"`
-	Object  string `json:"object"`
-	OwnedBy string `json:"owned_by"`
+	ID      string     `json:"id"`
+	Created int64      `json:"created"`
+	Object  string     `json:"object"`
+	OwnedBy string     `json:"owned_by"`
+	Meta    *ModelMeta `json:"meta,omitempty"`
+}
+
+// ModelMeta contains optional model metadata from the provider.
+// llama.cpp includes n_ctx (configured context size) and
+// n_ctx_train (model's native training context).
+type ModelMeta struct {
+	NCtx      int `json:"n_ctx,omitempty"`
+	NCtxTrain int `json:"n_ctx_train,omitempty"`
 }
 
 // ModelsResponse is the response for GET /models.