enhancement: password reset flow is missing

[shauryagangrade]

Problem

src/app/login/login-form.tsx offers sign-in, sign-up, and Google OAuth — but a forgotten password dead-ends. Email users who lose their password have no recovery path.

Suggested fix

• Add a "Forgot password?" toggle/action calling supabase.auth.resetPasswordForEmail() with ${siteUrl}/auth/callback?next=/... as redirect
• Handle the recovery/reauthentication auth event (e.g. land on an update-password state)
• Keep it inside the existing form's visual language

Acceptance criteria

• Email users can request a reset and set a new password