feat: unify doctor title handling and enhance specialty selection

- Implemented a helper function `displayDoctorName` to prepend "دکتر" to doctor names for consistent display across the application.
- Updated various components (InviteDoctorModal, DashboardPage, DoctorDetailPage, DoctorsPage, etc.) to utilize the new helper for rendering doctor names.
- Modified the DoctorFormPage to automatically add the "دکتر" title in the UI without requiring user input.
- Fixed the EditSpecialtyPicker component to allow multiple specialty selections, resolving a UI bug where only one specialty could be selected at a time.
- Ensured that the backend strips the "دکتر" title from the name during pre-registration and doctor creation processes.
- Added tests for the new functionality, including checks for title handling and specialty selection logic.
- Updated API documentation to reflect changes in name handling and display logic.

assets/admin/pages/DoctorFormPage.tsx

@@ -327,9 +327,19 @@ export default function DoctorFormPage() {
               <Field label="شماره موبایل" required error={errors.mobile?.message} hint="اگر کاربر با این شماره وجود دارد پروفایل به او متصل می‌شود">
                 <MobileInput hasError={!!errors.mobile} {...register('mobile')} />
               </Field>
-              <Field label="نام کامل" required error={errors.name?.message}>
-                <input type="text" className="cp-input" placeholder="دکتر ..." {...register('name')}
-                  style={errors.name ? { borderColor: 'var(--danger)' } : {}} />
+              <Field label="نام کامل" required error={errors.name?.message} hint="عنوان «دکتر» خودکار اضافه می‌شود؛ لازم نیست تایپ کنید">
+                <div className="cp-input" style={{
+                  display: 'flex', alignItems: 'center', gap: 6, padding: 0, overflow: 'hidden',
+                  ...(errors.name ? { borderColor: 'var(--danger)' } : {}),
+                }}>
+                  <span style={{
+                    flexShrink: 0, alignSelf: 'stretch', display: 'flex', alignItems: 'center',
+                    padding: '0 12px', background: 'var(--surface-2)', color: 'var(--text-2)',
+                    fontWeight: 600, fontSize: 14, borderInlineEnd: '1px solid var(--border)',
+                  }}>دکتر</span>
+                  <input type="text" placeholder="مثلاً: حامد حسینی" {...register('name')}
+                    style={{ flex: 1, minWidth: 0, border: 'none', outline: 'none', background: 'transparent', padding: '0 12px', height: '100%', color: 'inherit', font: 'inherit' }} />
+                </div>
               </Field>
             </div>
           </div>