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Description

Redesign the login flow based on deployment mode:

Fully Local Mode (VITE_USE_LOCAL_PROXY=true):

• Add /api/auto-login backend endpoint that returns the most recently active user or creates a default admin user
• Login page shows a "Start Eigent" button instead of email/password form
• Route guard auto-logs in when no token is present
• Default model type set to custom (not cloud) to avoid confusion
• Skip onboarding carousel/install screen after auto-login

Hybrid/App Mode (VITE_USE_LOCAL_PROXY=false):

• Login page redirects to eigent.ai/signin for authentication (decoupled from local auth)
• Electron main process starts a local HTTP server to receive auth callbacks with token
• Dev mode uses http://localhost callback; production uses eigent:// custom protocol
• After receiving token, fetches user profile from /api/user to populate username/email
• SignUp page redirects to eigent.ai/signup

Other changes:

• LoginResponse model adds optional redirect_url field (synced with eigent_server)
• History.tsx: Fix welcome name fallback (|| instead of ?? for empty string handling)

Testing Evidence (REQUIRED)

App Mode

• I have included human-verified testing evidence in this PR.
• This PR includes frontend/UI changes, and I
• No frontend/UI changes in this PR.

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Contribution Guidelines Acknowledgement

• I have read and agree to the Eigent Contribution Guideline