feat: Polish onboarding, tour and branch checkout flows

[charlesvien]

Problem

A grab-bag of onboarding and first session UX nits.

Changes

1. Add reusable CommandLine with copy button for CLI install steps
2. Standardize onboarding action button styling for consistency
3. Fix first-task product tour stuck on a step when its target element remounts
4. Surface dirty-tree precondition as a clear error on branch checkout
5. Toast on auto-unfocus failure during foreign branch checkout
6. Stop persisting cloud mode on cloud-repo deep link
7. Guard non-string account fields in GitHub settings

How did you test this?

Manually

Publish to changelog?

[charlesvien]

• fix: Handle SSH over HTTPS GitHub remote URLs #2049
• feat: Polish onboarding, tour and branch checkout flows #2047 👈 (View in Graphite)
• main

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[greptile-apps]

Prompt To Fix All With AI

Fix the following 2 code review issues. Work through them one at a time, proposing concise fixes.

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### Issue 1 of 2
apps/code/src/main/services/git/service.ts:307-318
**Heuristic can report the wrong error cause**

`getStatus` is called only after the checkout has already failed, so the presence of local changes isn't proof that they caused the failure. If checkout fails for an unrelated reason — e.g., the branch name doesn't exist locally (stale branch list), a git configuration error, or the saga returns an error for any other cause — but the working tree also happens to have modified files, `hasLocalChanges` will be `true` and a `PRECONDITION_FAILED` is thrown with "uncommitted changes would be overwritten". The user stashes their work, retries, and gets a completely different failure. Tying the error code to the presence of unrelated local changes produces actively misleading UX.

### Issue 2 of 2
apps/code/src/renderer/App.tsx:161-166
**Unhandled rejection if `disableFocus` throws**

The `onData` handler is `async` but has no `try/catch`. If `disableFocus` (or the underlying `runDisableFocusSaga`) throws instead of returning `{success: false}`, the exception propagates as an unhandled promise rejection and the toast is never shown. The result check only handles the "graceful failure" path; the exceptional path is uncovered. Wrapping in `try/catch` and showing a toast in the `catch` block would close this gap, in line with the project convention of always handling async failures.

_{Reviews (1): Last reviewed commit: "surface dirty-tree error on branch check..." | Re-trigger Greptile}