OpenPI 0.3.0

What's Changed

• fix: batch Resume UI layer installation by @tt-a1i in #25
• feat(footer): default to a one-line plain footer with a lighter layout by @tt-a1i in #26
• fix: keep deferred subagent results in timeline order by @tt-a1i in #30
• fix(subagents): release interactive turns while children run by @tt-a1i in #33
• Plan Mode 三项改进：指示器内联、必定可退出、bash 按副作用判定 by @tt-a1i in #31
• docs: define Pi-first agent contract by @tt-a1i in #35
• fix(subagents): keep compact results status-only by @tt-a1i in #38
• 子代理 UI 打磨：列表贴合内容、详情页去掉横线带、命令执行成块 by @tt-a1i in #36

Full Changelog: v0.2.0...v0.3.0