Implement the following plan:

# Stream Overlay: HTML-based OBS Skin for $ANKY Livestream

## Context
The current ffmpeg-based RTMP stream works (renders text on a dark background via drawtext) but is visually limited. We want a rich HTML overlay page that OBS captures via Browser Source — enabling the full anky game UI, stickers, animations, and branding. The ffmpeg stream stays as fallback.

## What Ships
A standalone HTML page at `/stream/overlay` that:
- Matches the anky writing game layout (dark bg, purple accents, Righteous font)
- Shows live writing text in real-time via SSE (big text, auto-scrolling)
- Life bar (idle countdown) + progress bar (8-min writing progress)
- `$ANKY` header branding
- 88:88 livestream timer with progress bar at bottom
- Contract address ticker at bottom
- Anky sticker images accumulate around the border as ankys are completed
- Vertical 1080x1920 layout (for pump.fun mobile viewing)