feat(app-shell): open chat by default

[kangfenmao]

What this PR does

Before this PR: Cherry Studio opened the main window with the Launchpad/Home tab selected and showed a dedicated Home icon plus separator in the tab bar.

After this PR: Cherry Studio opens directly to the chat tab, removes the dedicated Home tab-bar icon and separator, keeps sidebar navigation reusing the active main tab, and moves Launchpad access to the + tab action via /app/launchpad.

Fixes # N/A

Why we need it and why it was done in this way

The following tradeoffs were made: the old / and /home routes are removed instead of kept as compatibility aliases, matching the requested v2 navigation behavior.

The following alternatives were considered: keeping /home as a redirect or making + create another chat tab, but those did not match the desired startup and Launchpad behavior.

Links to places where the discussion took place: N/A

Breaking changes

No external API breaking changes. The user-visible startup route changes from Home/Launchpad to Chat, and Launchpad now lives at /app/launchpad.

Special notes for your reviewer

pnpm build:check passes. Existing legacy CSS variable warnings are still emitted by lint and are unrelated to this PR.

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR.
Approvers are expected to review this list.

• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Documentation: A user-guide update was considered and is present (link) or not required. Check this only when the PR introduces or changes a user-facing feature or behavior.
• Self-review: I have reviewed my own code (e.g., via /gh-pr-review, gh pr diff, or GitHub UI) before requesting review from others

Release note

Cherry Studio now opens directly to Chat instead of Launchpad/Home. Launchpad remains available from the `+` tab button. No action required.

[0xfullex]

Note

This comment was translated by Claude.

1. If the user has a pinned tab and was on that pinned tab when closing, the app should restore to that tab upon restart
2. If not the above case, after restart it can go to the last topic or topic list
   (Additionally, showing the homepage is the optimal choice, it's just that the current homepage hasn't implemented the functionality it should have)

Specifically, it's best to discuss and confirm with the product team.

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Original Content

1. 如果用户有pin的tab，并且关闭时停留在了pin的tab，则重新启动时应还原回到该tab
2. 如果非上述情况，重启后可以放到最后所在的topic，或topic列表
   （另外，放首页是最优选择，只是现在的首页还未实现其应该实现的功能而已）

具体的，最好是和产品一起讨论确认。

[kangfenmao]

Note

This comment was translated by Claude.

1. If the user has a pinned tab and was on that pinned tab when closing, the app should restore to that tab upon restart
2. If not the above case, after restart it can go to the last topic or topic list
   (Additionally, showing the homepage is the optimal choice, it's just that the current homepage hasn't implemented the functionality it should have)

Specifically, it's best to discuss and confirm with the product team.

This PR is only used to remove the default Tab. The PR has a single responsibility, and tab state persistence will be done in follow-up work.

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Original Content

这个 PR 仅用来移除默认的 Tab，PR 单一职责，tabs 的状态保持会放在后续来做

[EurFelux]

Note

This comment was translated by Claude.

Conflicts need to be resolved.

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Original Content

需要解决冲突