GitHub App install fails: blank page, org picker only after refresh, 404 on submit, app never installed

Preflight Checklist

• I have searched existing issues
• This is a single bug report
• This concerns the GitHub App install flow for Claude Code on web, not the CLI

What's Wrong?

The Claude GitHub App cannot be installed. The install flow initiated from claude.ai/code fails, and the app never appears as installed for my organization.

Observed sequence:

1. Clicking Install / Connect from claude.ai/code opens a blank white page.
2. The GitHub organization picker renders and MakeNashville is picked.
3. Submitting the picker returns a GitHub 404.
4. The app does not appear under Organization Settings > Third-party Access > GitHub Apps, nor under github.com/settings/installations.

What Should Happen?

The install link should render the GitHub installation target picker on first load, and submitting it should install the Claude GitHub App and redirect back to Claude successfully.

Steps to Reproduce

1. Go to claude.ai/code
2. Open the repository picker and start the GitHub connection / install flow
3. Select the target account or organization and submit
4. Observe a 404
5. Check github.com/settings/installations and the org's GitHub Apps page; Claude is absent

Account Context

• I am the owner of the organization
• Standard GitHub organization, NOT an Enterprise or EMU account, not GHE.com
• No third-party application access restrictions configured on the org
• GitHub username: kevinahuber
• Organization name: MakeNashville

Already Ruled Out

• Firefox with Enhanced Tracking Protection disabled for both claude.ai and github.com
• Chrome as an alternative browser
• Private / clean browsing window, single GitHub account signed in
• Direct navigation to github.com/apps/claude/installations/new
• Direct navigation to github.com/apps/claude/installations/select_target
• Both organization-wide and selected-repository grant scopes
• Org owner approval is not a factor since I am the owner

Environment

• Surface: Claude Code on web (claude.ai/code)
• Browser: Firefox
• OS / device: Android 16/Moto Razr Ultra 2025
• Plan: Pro

Request

Please advise whether this is a broken install callback or a backend repository index issue. If an account-side index reset is required, please trigger one.