fix: accept any letter case for password strength score 2

Score 2 (letters+digits >=8) previously only matched lowercase letters.
Now uses hasLetter = hasLower || hasUpper to match the spec's intent.
Added test case for uppercase-only + digits password.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/components/register/PasswordStrength.vue

@@ -11,7 +11,8 @@ const score = computed(() => {
   const hasDigit = /\d/.test(p)
   const hasSpecial = /[^a-zA-Z\d]/.test(p)
 
-  if (p.length >= 8 && hasLower && hasDigit) s = 2
+  const hasLetter = hasLower || hasUpper
+	if (p.length >= 8 && hasLetter && hasDigit) s = 2
   if (p.length >= 10 && hasLower && hasUpper && hasDigit) s = 3
   if (p.length >= 12 && hasLower && hasUpper && hasDigit && hasSpecial) s = 4
   // Fallback: any input < 8 or single-type = weak

app/components/register/__tests__/PasswordStrength.test.ts

@@ -25,6 +25,12 @@ describe('PasswordStrength', () => {
     expect(wrapper.text()).toContain('中')
   })
 
+  it('score 2 for uppercase letters+digits >= 8 chars', () => {
+    const wrapper = mount(PasswordStrength, { props: { password: 'ABC12345' } })
+    expect(wrapper.find('[data-testid="strength-bar"]').attributes('data-score')).toBe('2')
+    expect(wrapper.text()).toContain('中')
+  })
+
   it('score 3 for upper+lower+digits >= 10 chars', () => {
     const wrapper = mount(PasswordStrength, { props: { password: 'Abcdef1234' } })
     expect(wrapper.find('[data-testid="strength-bar"]').attributes('data-score')).toBe('3')