make some overall QoL improvements

public/market.html

@@ -102,7 +102,7 @@
     </main>
 
     <div id="marketPreviewModal" class="modal-overlay hidden">
-        <div class="modal-card market-preview-card">
+        <div class="modal-card market-preview-card" role="dialog" aria-modal="true" aria-labelledby="marketPreviewTitle" tabindex="-1">
             <div class="modal-header">
                 <div>
                     <p class="eyebrow">Persona preview</p>
@@ -162,7 +162,7 @@
     </div>
 
     <div id="marketPersonaModal" class="modal-overlay hidden">
-        <div class="modal-card persona-modal-card">
+        <div class="modal-card persona-modal-card" role="dialog" aria-modal="true" aria-labelledby="marketPersonaFormTitle" tabindex="-1">
             <div class="modal-header">
                 <div class="persona-modal-heading">
                     <p class="eyebrow">AI Character editor</p>