chore(frontend): refresh app launch assets

[Alexander-Noah]

变更说明

• 更新 Timeflow 应用主图标
• 更新 Android 自适应图标的背景色和前景图片配置
• 提交完整的 Android 背景、前景及单色替换图片
• 新增 android-icon-foreground-timeflow.png
• 删除旧的 splash-icon.png
• 移除通知配置中对应用主图标的显式引用

影响范围

仅涉及 Expo 配置和前端图片资源，不包含业务逻辑、后端或数据库变更。

与 Issue 的关系

• 关联 #403
• 与 PR #409 一起完成 Android 品牌图标资源统一的最终收口

验证

• 已确认所有配置引用的替换图片均包含在提交中

[LUPENGHAN]

ok

[fennoai]

The review covers the Expo Android icon configuration and all changed launch/notification assets. The config parses successfully and git diff --check is clean, but the adaptive icon layer contract has two Android-facing regressions noted inline.

Additional findings

• frontend/app.config.js:?: [P1] Use a transparent foreground-only adaptive icon asset: The new foregroundImage is the same full artwork as the replacement background and monochrome files: it contains an opaque beige rounded-square panel instead of only the transparent foreground artwork. Android/Expo composes this layer over backgroundColor and then applies the launcher mask, so the embedded panel defeats the background/foreground separation and can be clipped into the wrong shape on launchers using circular or other masks. Export a foreground-only PNG with the artwork in the adaptive safe zone and transparent pixels elsewhere.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Flag	Coverage Δ
backend	?
frontend	90.38% <ø> (ø)

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