UI: Centralize alerts, field errors, and status dots

[Ayush4958]

Description

It solves the issue by centralizing the duplicated UI components scattered across the setup wizard, settings & dashboard. It introduces a unified, scalable design system using class-variance (CV) to eliminate raw Tailwind class duplication.

Closes :- #178

Changes Made

• New Components :-
  • <Alert>: Replaces 15+ duplicated warning/success/error banners. Supports neutral, info, warning, destructive & success variants with automatic ARIA roles.
  • <FieldError>: Replaces 20+ inline <p className="text-destructive"> form validation error messages across the setup forms.
  • <StatusDot>: Unifies the connection status indicators in the Shell, ConfigurationTab, and ConnectionStatus components.
• Refactoring: Migrated all Setup Wizard steps, Configuration Tab, and the Unified Dashboard to use the new component suite.

Validation

• npm run typecheck passes with no unused imports.
• npm run lint passes with 0 warnings.
• Tested locally.

[Ayush4958]

@pavlenex @lucasbalieiro

I had refactored it and check it manually and it works fine
I had not touch any functionality / working function
I purely focused on refactoring the ui component and tried to make them re-usable

PR is ready for review, take time for it
Thanks ....

[lucasbalieiro]

@Ayush4958, thanks. I'll start reviewing it today.

In the meantime, could you rebase the PR and solve the conflicts to avoid adding this merge commits: Merge branch 'main' of https://github.com/stratum-mining/sv2-ui

Because they are polluting the diff that I want to review.

[Ayush4958]

sorry @lucasbalieiro for late reply
I had rebased the PR, Its ready for review
thanks ..

[lucasbalieiro]

This is going in the right direction. I've left a few comments regarding some changes around the drop of the alert for "Review your setup to continue mining. Your saved settings are prefilled".

This might introduce a regression that was fixed in #234.

Please avoid dropping the error messages even if they seem alike, let's focus only on reorganizing the ui components

[Ayush4958]

thanks for catching,
I had fixes everything and changes are ready to review

[lucasbalieiro]

ACK