feat: reaction TDS styling, debounce read receipts, Escape to skip boot, type fixes

- lotus-terminal.css.ts: add reaction chip styles for dark + light TDS modes
  (cyan border/bg for unselected, orange accent for own/pressed reactions)
- useRoomReadPositions: debounce receipt handler at 150ms (M-3)
- lotus-boot.ts: Escape key skips boot animation (I-3)
- RoomInput.tsx: replace (uploadRes as any) with typed assertion (M-7)
- CallEmbedProvider: call mention detection, audio cleanup, display name (C-1, C-2, M-5)
- EventReaders: timestamps in seen-by modal, filter self, TDS styling
- ReadReceiptAvatars: StackedAvatar pill, TDS visual treatment
- chatBackground: add waves/neon/aurora backgrounds
- RoomView: auto-apply tactical bg when TDS active and bg is none
- settings: extend ChatBackground union type

src/app/features/room/RoomInput.tsx

@@ -475,7 +475,7 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
             new File([blob], 'image.gif', { type: 'image/gif' }),
             { type: 'image/gif', name: 'image.gif', includeFilename: false }
           );
-          const mxcUrl = (uploadRes as any).content_uri;
+          const mxcUrl = (uploadRes as { content_uri: string }).content_uri;
           if (!mxcUrl) return;
           mx.sendMessage(roomId, {
             msgtype: MsgType.Image,