feat: Développer le composant Datepicker (#52)

| Numéro du ticket | Titre du ticket |
|------------------|-----------------|
|                  |                 |

## Description de la PR

## Modification du .env

## Check list

- [ ] Pas de régression
- [ ] TU/TI/TF rédigée
- [ ] TU/TI/TF OK
- [ ] CHANGELOG modifié

Co-authored-by: matthieu <matthieu@yuno.malio.fr>
Co-authored-by: THOLOT DECHENE Matthieu <matthieu@yuno.malio.fr>
Reviewed-on: #52
Co-authored-by: tristan <tristan@yuno.malio.fr>
Co-committed-by: tristan <tristan@yuno.malio.fr>

app/components/malio/date/composables/useCalendarPopover.test.ts

@@ -0,0 +1,64 @@
+import {describe, expect, it} from 'vitest'
+import {defineComponent, h, ref} from 'vue'
+import {mount} from '@vue/test-utils'
+import {useCalendarPopover} from './useCalendarPopover'
+
+const mountHost = () => {
+  const api: ReturnType<typeof useCalendarPopover> = {} as never
+  const Host = defineComponent({
+    setup() {
+      const root = ref<HTMLElement | null>(null)
+      Object.assign(api, useCalendarPopover(root))
+      return () => h('div', {ref: root}, 'host')
+    },
+  })
+  const wrapper = mount(Host, {attachTo: document.body})
+  return {wrapper, api}
+}
+
+describe('useCalendarPopover', () => {
+  it('starts closed in days view', () => {
+    const {api} = mountHost()
+    expect(api.isOpen.value).toBe(false)
+    expect(api.viewMode.value).toBe('days')
+  })
+
+  it('open() opens in days view', () => {
+    const {api} = mountHost()
+    api.open()
+    expect(api.isOpen.value).toBe(true)
+    expect(api.viewMode.value).toBe('days')
+  })
+
+  it('toggleView() switches between days and months', () => {
+    const {api} = mountHost()
+    api.open()
+    api.toggleView()
+    expect(api.viewMode.value).toBe('months')
+    api.toggleView()
+    expect(api.viewMode.value).toBe('days')
+  })
+
+  it('close() resets isOpen and viewMode', () => {
+    const {api} = mountHost()
+    api.open()
+    api.toggleView()
+    api.close()
+    expect(api.isOpen.value).toBe(false)
+    expect(api.viewMode.value).toBe('days')
+  })
+
+  it('closes on outside mousedown', () => {
+    const {api} = mountHost()
+    api.open()
+    document.body.dispatchEvent(new MouseEvent('mousedown', {bubbles: true}))
+    expect(api.isOpen.value).toBe(false)
+  })
+
+  it('stays open on inside mousedown', () => {
+    const {wrapper, api} = mountHost()
+    api.open()
+    wrapper.element.dispatchEvent(new MouseEvent('mousedown', {bubbles: true}))
+    expect(api.isOpen.value).toBe(true)
+  })
+})