feat(web): unify attachment open behavior in context menus

docs/core-checklist-status.md

@@ -22,7 +22,7 @@ Legend:
 13. Reactions - `DONE`
 14. Delivery Status - `DONE` (sent/delivered/read + reconnect reconciliation after backend restarts)
 15. Typing Realtime - `DONE` (web: typing start/stop + recording voice start/stop; `recording_video_*` remains for mobile circle-video clients)
-16. Media & Attachments - `DONE` (upload/preview/download/gallery; sticker/GIF inline media no longer opens photo viewer on click; Chat Info and message context menus use blob-download flow with success/error toasts)
+16. Media & Attachments - `DONE` (upload/preview/download/gallery; sticker/GIF inline media no longer opens photo viewer on click; Chat Info and message context menus now have consistent `Open/Download/Copy` behavior with menu auto-close and download toasts)
 17. Voice Messages - `PARTIAL` (record/send/play/seek + global speed 1x/1.5x/2x; recorder uses improved mime priority for better duration metadata; backend media allowlist includes `audio/mp4`/`audio/x-m4a`; audio store tracks duration via `durationchange/seekable` fallback; websocket send/recorder stop race on fast chat switch is guarded; UX still being polished)
 18. Circle Video Messages - `PARTIAL` (mobile-priority only: backend type/realtime supported; web composer intentionally does not send circles)
 19. Stickers - `PARTIAL` (web sticker picker with preset pack + favorites)

web/src/components/ChatInfoPanel.tsx

@@ -987,9 +987,16 @@ export function ChatInfoPanel({ chatId, open, onClose }: Props) {
           style={{ left: attachmentCtx.x, top: attachmentCtx.y }}
           onClick={(event) => event.stopPropagation()}
         >
-          <a className="block rounded px-2 py-1.5 text-sm hover:bg-slate-800" href={attachmentCtx.url} rel="noreferrer" target="_blank">
+          <button
+            className="block w-full rounded px-2 py-1.5 text-left text-sm hover:bg-slate-800"
+            onClick={() => {
+              window.open(attachmentCtx.url, "_blank", "noopener,noreferrer");
+              setAttachmentCtx(null);
+            }}
+            type="button"
+          >
             Open
-          </a>
+          </button>
           <button
             className="block w-full rounded px-2 py-1.5 text-left text-sm hover:bg-slate-800"
             onClick={async () => {

web/src/components/MessageList.tsx

@@ -807,9 +807,20 @@ export function MessageList() {
               {ctx.attachmentUrl ? (
                 <>
                   <div className="my-1 h-px bg-slate-700/80" />
-                  <a className="block w-full rounded px-2 py-1.5 text-left text-sm hover:bg-slate-800" href={ctx.attachmentUrl} rel="noreferrer" target="_blank">
+                  <button
+                    className="block w-full rounded px-2 py-1.5 text-left text-sm hover:bg-slate-800"
+                    onClick={() => {
+                      const url = ctx.attachmentUrl;
+                      if (!url) {
+                        return;
+                      }
+                      window.open(url, "_blank", "noopener,noreferrer");
+                      setCtx(null);
+                    }}
+                    type="button"
+                  >
                     Open media
-                  </a>
+                  </button>
                   <button
                     className="block w-full rounded px-2 py-1.5 text-left text-sm hover:bg-slate-800"
                     onClick={async () => {