🤖 perf: improve small-screen UX and reduce mobile CPU spikes

[ibetitsmike]

What

Mobile + small-screen improvements:

• iOS safe-area header bleed: add a .safe-area-top-bleed utility and apply it to top bars so the header background extends into the notch area without clipping interactive content.
• Disable right sidebar on small screens (<= 768px):
  • Don’t render <RightSidebar />.
  • Hide right-sidebar command palette actions.
  • Route “open terminal” to the terminal popout instead of trying to target the sidebar.
• Mobile performance quick wins:
  • Avoid O(n²) bash_output grouping scans in ChatPane by computing group info in one pass.
  • Add a large-file fast path to TextFileViewer (render raw <pre> with an explicit opt-in to full render).
  • Skip git-status subscriptions in the workspace list on small screens.

Why

On mobile / small screens the right sidebar is not usable and large chats/files can cause CPU spikes and jank. These changes prioritize:

• keeping the top bar usable on iOS notch devices
• preventing inaccessible UI from mounting on small screens
• reducing worst-case render work in long transcripts, large files, and large workspace lists

Validation

• make static-check

---

Generated with mux • Model: openai:gpt-5.2 • Thinking: high • Cost: $8.32

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 8a02d96781

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[ibetitsmike]

@codex review

Handled the small-screen terminal popout path with a best-effort .catch(() => undefined) to avoid unhandled promise rejections.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 460ba760c7

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[ibetitsmike]

@codex review

Updated TextFileViewer large-file fast path to key the “render highlighted” override by filePath, so switching files immediately re-enables the fast path (no one-render CPU spike).

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 59eb44e2ec

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[ibetitsmike]

@codex review

Scoped the large-file “render highlighted” override by workspaceId + relativePath (passed through FileViewerTab), so identical paths in different workspaces won’t bypass the fast path.

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Bravo.

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".