feat(central-ui): enlarge script modal; tab the Shared Script form

Script editor modal (TemplateEdit): the tabbed Trigger/Code/Parameters/
Return content is substantial, so the dialog now fills most of the
viewport — a .script-editor-modal class (96vw wide, ~full height) replaces
modal-xl, paired with modal-dialog-scrollable so the body scrolls.

Shared Script create/edit form (SharedScriptForm): Code, Parameters, and
Return type move from stacked sections into a tab strip, matching the
template script modal. Panels toggle via display:none so the Monaco editor
and JSONJoy island stay mounted across tab switches; Code is the default
tab. Name stays above the tabs.

Markup/CSS only — no logic change. CentralUI suite 316 green; both
verified in the browser.

src/ScadaLink.CentralUI/Components/Pages/Design/TemplateEdit.razor

@@ -863,7 +863,7 @@
         {
             var editingScript = _editScriptId.HasValue;
             <div class="modal show d-block" tabindex="-1" style="background: rgba(0,0,0,0.4);">
-                <div class="modal-dialog modal-xl modal-dialog-scrollable">
+                <div class="modal-dialog modal-dialog-scrollable script-editor-modal">
                     <div class="modal-content">
                         <div class="modal-header">
                             <h6 class="modal-title">@(editingScript ? "Edit Script" : "Add Script")</h6>