feat(ui) : état readonly visuel sur pickers date/heure

Bordure noire forcée (même vide), suppression du bleu focus/primary, label
et icône en text-black si rempli sinon text-m-muted, float piloté par isFilled
uniquement en readonly. Bouton clear et astérisque inchangés.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/components/malio/time/TimePicker.test.ts

@@ -83,4 +83,30 @@ describe('MalioTimePicker', () => {
     const wrapper = mountPicker({label: 'Champ'})
     expect(wrapper.find('[data-test="required-mark"]').exists()).toBe(false)
   })
+
+  it('readonly vide : bordure noire sans bleu', () => {
+    const wrapper = mountPicker({readonly: true})
+    const input = wrapper.get('[data-test="time-field"]')
+    expect(input.classes()).toContain('border-black')
+    expect(input.classes()).not.toContain('border-m-muted')
+    expect(input.classes()).not.toContain('focus:border-m-primary')
+  })
+
+  it('readonly vide : label muted sans bleu', () => {
+    const wrapper = mountPicker({readonly: true, label: 'Heure'})
+    const label = wrapper.get('label')
+    expect(label.classes()).toContain('text-m-muted')
+    expect(label.classes()).not.toContain('text-m-primary')
+  })
+
+  it('readonly rempli : label et icône en noir, bordure noire', () => {
+    const wrapper = mountPicker({readonly: true, label: 'Heure', modelValue: '14:30'})
+    const input = wrapper.get('[data-test="time-field"]')
+    const label = wrapper.get('label')
+    const icon = wrapper.get('[data-test="clock-icon"]')
+    expect(input.classes()).toContain('border-black')
+    expect(input.classes()).not.toContain('focus:border-m-primary')
+    expect(label.classes()).toContain('text-black')
+    expect(icon.classes()).toContain('text-black')
+  })
 })