Fixes slow when import html on upgrade (TiddlyWiki#9689)

* Short-circuit the import option; only show it when you click a button

* Add aira-label

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* perf(import): lazy evaluate import options panel, shortcircuit when no options, and flatten let widgets

- Only parse $:/Import JSON when user expands the import options panel
- Skip all import option logic if no $:/tags/ImportOptions tiddlers exist
- Merge nested let widgets into single multi-variable let for better performance and readability
- Add lingo for import options panel and no-match message

This greatly improves import speed for large wikis, especially when no import options are present.

* fix(import): use correct transclusion for aria-label on import options panel buttons\n\nBind aria-label using {{$:/language/Import/Listing/ImportOptions/Caption}} instead of macro literal, matching TiddlyWiki convention and ensuring accessibility tools read the correct label.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: linonetwo

core/language/en-GB/Import.multids

@@ -15,6 +15,8 @@ Listing/Preview/TextRaw: Text (Raw)
 Listing/Preview/Fields: Fields
 Listing/Preview/Diff: Diff
 Listing/Preview/DiffFields: Diff (Fields)
+Listing/ImportOptions/Caption: Import options
+Listing/ImportOptions/NoMatch: No import options apply to these files.
 Listing/Rename/Tooltip: Rename tiddler before importing
 Listing/Rename/Prompt: Rename to:
 Listing/Rename/ConfirmRename: Rename tiddler

core/ui/ImportListing.tid

@@ -49,23 +49,40 @@ title: $:/core/ui/ImportListing
 \end
 
 \whitespace trim
-<$let importJson={{{ [{$:/Import}] }}}
-	importTitles={{{ [<importJson>jsonindexes[tiddlers]] }}}
-	importTypes={{{ [(importTitles)] :map[<importJson>jsonget[tiddlers],<currentTiddler>,[type]] }}}
-	anyMatch={{{ [all[shadows+tiddlers]tag[$:/tags/ImportOptions]get[condition]] :map[(importTypes)subfilter<currentTiddler>] +[!is[blank]limit[1]] }}}>
-	<%if [<anyMatch>!is[blank]] %>
-		<div class="tc-import-option">
-			<$list filter="[all[shadows+tiddlers]tag[$:/tags/ImportOptions]]" variable="importOption">
-				<$let condition={{{ [<importOption>get[condition]] }}}
-					hasMatch={{{ [(importTypes)subfilter<condition>limit[1]] }}}>
-					<%if [<hasMatch>!is[blank]] %>
-						<$transclude tiddler=<<importOption>>/>
-					<%endif%>
-				</$let>
-			</$list>
-		</div>
-	<%endif%>
-</$let>
+<%if [all[shadows+tiddlers]tag[$:/tags/ImportOptions]limit[1]] %>
+	<$reveal type="nomatch" state="$:/state/import/options" text="yes" tag="div">
+		<$button class="tc-btn-invisible tc-btn-dropdown" set="$:/state/import/options" setTo="yes" aria-label={{$:/language/Import/Listing/ImportOptions/Caption}} aria-expanded="false">
+			<span class="tc-small-gap-right">{{$:/core/images/right-arrow}}</span><<lingo Listing/ImportOptions/Caption>>
+		</$button>
+	</$reveal>
+	<$reveal type="match" state="$:/state/import/options" text="yes" tag="div">
+		<$button class="tc-btn-invisible tc-btn-dropdown" set="$:/state/import/options" setTo="no" aria-label={{$:/language/Import/Listing/ImportOptions/Caption}} aria-expanded="true">
+			<span class="tc-small-gap-right">{{$:/core/images/down-arrow}}</span><<lingo Listing/ImportOptions/Caption>>
+		</$button>
+		<$let importJson={{{ [{$:/Import}] }}}
+			importTitles={{{ [<importJson>jsonindexes[tiddlers]] }}}
+			importTypes={{{ [(importTitles)] :map[<importJson>jsonget[tiddlers],<currentTiddler>,[type]] }}}
+			anyMatch={{{ [all[shadows+tiddlers]tag[$:/tags/ImportOptions]get[condition]] :map[(importTypes)subfilter<currentTiddler>] +[!is[blank]limit[1]] }}}>
+			<%if [<anyMatch>!is[blank]] %>
+				<div class="tc-import-option">
+					<$list filter="[all[shadows+tiddlers]tag[$:/tags/ImportOptions]]" variable="importOption">
+						<$let condition={{{ [<importOption>get[condition]] }}}
+							hasMatch={{{ [(importTypes)subfilter<condition>limit[1]] }}}>
+							<%if [<hasMatch>!is[blank]] %>
+								<$transclude tiddler=<<importOption>>/>
+							<%endif%>
+						</$let>
+					</$list>
+				</div>
+			<%else%>
+				<div class="tc-import-option">
+					<<lingo Listing/ImportOptions/NoMatch>>
+				</div>
+			<%endif%>
+		</$let>
+	</$reveal>
+<%endif%>
+
 <div class="tc-table-wrapper">
 <table class="tc-import-table">
 <tbody>