Add client-side form validation with inline error messaging

[Dannyswiss1]

Forms across PatientSearch (access request modal), RecordsPage (add record), and ProviderProfile (add staff)
currently only disable the submit button when required fields are empty — there's no inline feedback explaining
why, and no format validation (e.g. email format, passport ID shape). Add a small shared validation helper and
inline error text under each invalid field, shown after first blur/submit attempt.

Acceptance criteria

• Email fields validate format, not just non-empty
• Passport ID input validates against the expected pp_... shape
• Errors are shown per-field, not just via a disabled button, and are associated via aria-describedby