Agent Duel 0.4.0-beta.7

What's Changed

• Preserve upstream inference costs alongside account charges by @micjm in #51
• fix(arena): bring a battle chat back when it is unarchived by @lokicik in #47
• fix(arena): name battle chats from the first summary by @lokicik in #60
• fix(arena): run contestant subagents concurrently by @vikas-bottomless in #59
• chore(release): cut 0.4.0-beta.7 by @vikas-bottomless in #61

Full Changelog: v0.4.0-beta.6...v0.4.0-beta.7