feat(translate): add translation presets and custom instructions

src/settings/qtpotatosettings.kcfg

@@ -122,6 +122,14 @@
       <label>Language to translate subtitles into, written for the model</label>
       <default>Vietnamese</default>
     </entry>
+    <entry name="TranslationPreset" type="String">
+      <label>Style preset used by the subtitle translation prompt</label>
+      <default>general</default>
+    </entry>
+    <entry name="CustomInstructions" type="String">
+      <label>Additional instructions for subtitle translation</label>
+      <default></default>
+    </entry>
     <entry name="BatchSize" type="Int">
       <label>Subtitle lines sent per request</label>
       <default>40</default>