New customer onboarding signup, login, and reset-password screens

First-impression screens have been re-designed and hardened against a long tail of edge cases.

• Signup, login, and reset-password share a single visual system that matches the rest of the new dashboard theme.
• Phone number validation supports country codes, distinguishes between local and international formats, and works for OAuth signups (Google/GitHub) where the phone number was previously discarded.
• The final signup step now lands on the workspace landing page directly instead of a half-rendered intermediate page.
• Country-code parsing was fixed for users who paste a number with the ”+” prefix already present.
• Form alignment and dollar-sign rendering on currency inputs have been resolved across all auth screens.

Existing users see no flow changes; new signups go through the refreshed experience.