feat: Add temporary system prompt

Adds a new setting that allows users to set a temporary system prompt for the current chat.
This prompt will override the selected system prompt if it exists.
The new setting is available in the "Current Chat Model Settings" modal.
This feature provides a way to quickly experiment with different system prompts without having to change the default setting.

src/assets/locale/es/common.json

@@ -85,6 +85,11 @@
             "numGpu": {
                 "label": "Num GPU",
                 "placeholder": "Ingrese el número de capas para enviar a la(s) GPU(s)"
+            },
+            "systemPrompt": {
+                "label": "Prompt de Sistema Temporal",
+                "placeholder": "Ingrese el Prompt de Sistema",
+                "help": "Esta es una forma rápida de establecer el prompt de sistema en el chat actual, que anulará el prompt de sistema seleccionado si existe."
             }
         },
         "advanced": "Más Configuraciones del Modelo"