Stream the media grid with a scroll buffer

docs/media.md

@@ -175,9 +175,14 @@ that deletion is irreversible. The delete button is disabled for a 5 second coun
   can take its place while the hidden one stays resumable. The strip text turns red and reads
   `API limited, retry in Ns` while Discord throttles media traffic, and a translucent
   `N scrapes completed` line appears when scrapes finish — it lives until the tab is reloaded. Each
-  row shows `X/Yp (~Z%)` when the search total is known. The grid scrolls infinitely
-  (a **Load more** button appears as a fallback). Media whose source answers `403` shows a
-  **PRIVATE** tile and `404`/`410` shows **GONE**, with the reason in the tooltip. Some channels deny the bot the search endpoint (`Missing Access`) even though history
+  row shows `X/Yp (~Z%)` when the search total is known. The grid streams: appending a page inserts
+  only the new cards, so loaded images never rebuild or flash, and a stream **buffer** below the last
+  row keeps the scroll alive while the next page is in flight. The buffer is capped at 1.5 viewport
+  heights, shrinks as the filtered results run out, and says `Loading more…` / `Scroll for more` /
+  `End of results`; auto-fill cascades pages while the buffer is still in view, so a filter that
+  returns few items does not dead-stop at one page. At the very bottom while a page loads, an
+  elastic nudge replaces the hard stop. Media whose source answers `403` shows a **PRIVATE** tile
+  and `404`/`410` shows **GONE**, with the reason in the tooltip. Some channels deny the bot the search endpoint (`Missing Access`) even though history
   reads work, so the total is optional.
   **New scrape…** (rightmost) opens a popup with Server and Group chat trees (servers expand to
   channels; each row has Links and Download). Every scrape button asks for confirmation; the