feat: integrate react-hook-form and zod across all forms

[OTimileyin]

Closes #247

Summary

• Replaces all ad-hoc useState validation logic with react-hook-form + zod across all 8 forms
• Introduces a shared components/ui/Input component with error prop + forwarded ref, used consistently across all forms
• All validation schemas live in lib/validations/ with exported TypeScript types

Forms migrated

#	Form	Path
1	Login	app/(auth)/login/page.tsx
2	Signup	app/(auth)/signup/page.tsx
3	Forgot Password	app/(auth)/forgot-password/page.tsx
4	Reset Password	app/(auth)/reset-password/page.tsx
5	Convert	components/dashboard/convert/convert-form.tsx
6	Withdrawal	components/dashboard/withdrawal/WithdrawalForm.tsx
7	Settings Profile	components/profile/profile-edit-form.tsx
8	Admin Push Notification	components/admin/push-notifications/CreatePushNotificationModal.tsx

Shared schema approach

Schemas in lib/validations/:

• auth.ts — login, signup, forgot-password, reset-password
• transactions.ts — convert, withdrawal
• profile.ts — settings profile
• notifications.ts — admin push notification

Each schema exports inferred TypeScript types used as useForm<T> generics.

Validation pattern

Every form uses useForm({ resolver: zodResolver(schema) }). Field errors are passed to the Input component's error prop, which renders the message inline below each field. Input uses React.forwardRef so RHF's register() can attach refs correctly.

Notable: Reset Password OTP

The OTP field preserves the 6-digit custom input UX (individual boxes + auto-focus). A hidden <input type="hidden"> is registered with RHF and synced via setValue("otp", digits.join("")) as digits change, so zodResolver validates the joined 6-digit string against z.string().length(6).

No ad-hoc validation remains

Confirmed via grep — zero occurrences of useState.*errors, setErrors, validateForm(), or inline regex guards across all 8 forms.

Verification

• npm run build ✅ — TypeScript + compile, 0 errors
• npm run lint ✅ — 0 errors (2 React Compiler watch() warnings are an expected known limitation with RHF)

This PR targets v2, not main.

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[portableDD]

@OTimileyin please esolve conflivts

[portableDD]

This PR has merge conflicts. Please rebase on latest v2 and fix the conflicts.

[portableDD]

This PR has merge conflicts. Please rebase on latest v2 and fix the conflicts.

[portableDD]

This PR has merge conflicts. Please rebase on latest v2 and fix the conflicts.

[portableDD]

This PR has merge conflicts. Please rebase on latest v2 and fix the conflicts.

[portableDD]

This PR has extensive merge conflicts with v2. Please rebase your branch on the latest v2 and resolve the conflicts so it can be merged.