_best_portrait_url was falling back to non-GIF screenshots when both
coverUrl and stillCoverUrl were GIFs. Screenshots are not capsule art,
so this produced wrong imagery. Now the function only returns cover
URLs and returns empty when only GIFs are available.
When all available cover URLs are GIFs (coverUrl, stillCoverUrl, and
screenshots), return empty instead of a GIF URL. HTTPImageFetcher cannot
decode GIFs, so attempting to fetch one always returns null. Returning
empty early avoids unnecessary network requests and confusing log noise.
butlerd sometimes passes itch.io coverUrl/stillCoverUrl with trailing
srcset descriptors (e.g. ' 1x, h' or ' 1'). These polluted URLs cause
HTTPImageFetcher to fail because the URL is invalid and the extension
extraction breaks.
Changes:
- Add _sanitize_url() to strip srcset artifacts from URLs
- Add _is_gif_url() helper that works with both clean and polluted URLs
- Fix SCREENSHOT_REGEX_PATTERN to use [\w+/=]* instead of [^"]* to
avoid crossing srcset boundaries in HTML
- Replace all .ends_with('.gif') checks with _is_gif_url()
- Sanitize all URLs from game metadata and HTML scraping
- Add IMAGE_EXTS constant for extension validation
Also bump to v0.1.7.
