Prereleases hidden by default; version selection fixed

Added

• Collections now show up in search results across the web, API, MCP server, and CLI.
• Release notes now render GitHub-flavored extras — note/warning callouts, emoji shortcodes, and @user and org/repo#123 autolinks.
• Feed lists show a small +N indicator when a release bundles related coverage from other sources.
• AI summaries now appear as a clearly labeled block above the release body.

Changed

• Prereleases like alphas, betas, and RCs are hidden by default, and version ranges render as a clear before-and-after diff.

Fixed

• The Latest version and version range now pick the highest semantic version instead of the most recently published, so backported patches no longer masquerade as the newest release.