mtg_python_deckbuilder/docs/releases/v4.5.2.md

# MTG Python Deckbuilder v4.5.2

## Summary
Adds hover-intent prefetch for the Open Deck button on the Finished Decks page, reducing perceived load time when navigating into a deck view.

## Added

### Hover-intent prefetch (`WEB_PREFETCH=1`)
Hovering over an "Open" button on the Finished Decks page now prefetches the deck view in the background after a 100 ms delay. When you click, the page loads from the browser's prefetch cache rather than waiting on a network round-trip — making it feel near-instant.

- Off by default; enable with `WEB_PREFETCH=1`
- Respects `Save-Data` header and slow (2G) connections — no prefetch on metered/slow connections
- Limits concurrent prefetches to 2
- Speculation Rules API infrastructure included for future side-effect-free GET routes
- `Cache-Control: private, max-age=30` added to `/decks/view` when flag is enabled

## Configuration

| Variable | Default | Description |
|---|---|---|
| `WEB_PREFETCH` | `0` | Set to `1` to enable hover-intent prefetch on the Open Deck button |