feat: implement web auth flow UI and interactions

[erinc00]

Summary

This PR implements the web auth flow for NEPH.

Included

• auth layout and welcome screen
• login page
• signup page
• verify email page
• forgot password page
• terms of service and privacy policy pages
• guest mode placeholder
• social auth placeholders
• continue with email flow
• email, phone number, and verification code validation improvements
• signup draft restore flow when returning from verify email
• responsive auth layout and showcase improvements

Notes

• Guest mode is currently a placeholder for MVP.
• Social login buttons are UI placeholders and are not connected to real OAuth providers yet.
• A related shared UI fix PR exists and is expected to be merged first if needed.

[gulcetahtasiz]

Great work overall, the auth flow structure and UI look clean and well thought out

I have a couple of points:

1. Merge conflict (blocking)
   There is an unresolved merge conflict in globals.css that needs to be fixed before this PR can be merged.
   It looks like both branches modified the same button styles. Please make sure to keep the base button reset styles from development (instead of the commented version) to maintain UI consistency.

2. UX improvement (non-blocking)
   Nice work on the signup flow, especially the draft restore after email verification.
   I noticed a UX issue: when filling the signup form and navigating to Terms of Service or Privacy Policy, returning back resets all form inputs. This can lead to loss of user input and may be frustrating.

Thanks for the effort

[kckagancan]

• Component and filename mismatch at AuthShowCase.tsx (func name AuthShowcase)

At SignupForm.tsx:

• sessionStorage holds password which is an issue
• There is no cleanup for setTimeout
• Password is logged which is an issue

At SelectInput.tsx:

• label and shortLabel are made mandatory which is not a good idea I think.
• key generation is little too complex
• className goes to invisible select

[erinc00]

Great work overall, the auth flow structure and UI look clean and well thought out

I have a couple of points:

1. Merge conflict (blocking)
   There is an unresolved merge conflict in globals.css that needs to be fixed before this PR can be merged.
   It looks like both branches modified the same button styles. Please make sure to keep the base button reset styles from development (instead of the commented version) to maintain UI consistency.
2. UX improvement (non-blocking)
   Nice work on the signup flow, especially the draft restore after email verification.
   I noticed a UX issue: when filling the signup form and navigating to Terms of Service or Privacy Policy, returning back resets all form inputs. This can lead to loss of user input and may be frustrating.

Thanks for the effort

resolved the restore issue for Terms of Service / Privacy Policy navigation
synced naming / component fixes and updated auth flow behavior

[erinc00]

• Component and filename mismatch at AuthShowCase.tsx (func name AuthShowcase)

At SignupForm.tsx:

• sessionStorage holds password which is an issue
• There is no cleanup for setTimeout
• Password is logged which is an issue

At SelectInput.tsx:

• label and shortLabel are made mandatory which is not a good idea I think.
• key generation is little too complex
• className goes to invisible select

fixed AuthShowcase filename mismatch
removed auth payload logging
removed password from signup draft storage
added timeout cleanup
revised SelectInput API and behavior

[erinc00]

Addressed the review comments and synced the branch with the latest development.

Updates include:

• resolved merge conflicts
• fixed signup draft restore for Terms of Service / Privacy Policy navigation
• removed password from session storage
• removed auth payload logging
• added timeout cleanup
• fixed AuthShowcase filename mismatch
• revised SelectInput, Checkbox, and VerificationCodeInput while preserving the latest shared color updates

[gulcetahtasiz]

Tested the flow, everything is working smoothly. Great job, ready to merge

[kckagancan]

Looks good now. Merging.