Render media dialogs above the settings slide-over

docs/webui.md

@@ -123,8 +123,9 @@ box live in Chat, not Call, and the connection stats are not chips yet.
 
 - **Media** and **Bot** are scope buttons beside Guild and DM. They open a full-window view below
   the header and the call strip (the shell is covered; only the header, and the call strip when it
-  is visible, stay on screen). Settings slides over the media view. Mobile is out of scope for the
+  is visible, stay on screen). Settings slides over the media view, and dialogs that Settings
-  media feature.
+  opens (for example **Clean media…**) render above Settings. Mobile is out of scope for the media
+  feature.
 - Media lists scraped items with kind chips (All, Images, GIFs, Videos, Audio) and filters for
   source (any, attachments, stickers, embeds), source channel, poster, aspect ratio, resolution,
   and a posted-date range (from/to). **New scrape…** opens a popup with **Server** and **Group

poc/public/media.css

@@ -340,7 +340,8 @@
 .vk-media-modal {
     position: fixed;
     inset: 0;
-    z-index: 95;
+    /* Above the settings slide-over (1000): Clean media and other dialogs open from Settings. */
+    z-index: 1050;
     display: flex;
     align-items: center;
     justify-content: center;

poc/public/style.css

@@ -1580,8 +1580,8 @@ a.vk-attachment:hover {
 
 /*
  * Layering scale, highest wins:
- *   chrome 40 · media view 70 · media modals 95 · settings 1000 · toasts 1100
+ *   chrome 40 · media view 70 · settings 1000 · dialogs opened from settings 1050 · toasts 1100
- * Any new full-screen layer should pick a slot below 1000, not above the dialogs.
+ * A full-screen layer sits below 1000 unless it is a dialog that Settings itself opens.
  */
 .vk-overlay {
     position: fixed;