[#202] Authentification — Connexion utilisateur (JWT) (!5)

| Numéro du ticket | Titre du ticket |
|------------------|-----------------|
|      #202            |        Authentification — Connexion utilisateur (JWT)         |

## Description de la PR
[#202] Authentification — Connexion utilisateur (JWT)

## Modification du .env

## Check list

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

Reviewed-on: https://gitea.malio.fr/MALIO-DEV/Ferme/pulls/5
Reviewed-by: THOLOT DECHENE Matthieu <matthieu@yuno.malio.fr>
Co-authored-by: tristan <tristan@yuno.malio.fr>
Co-committed-by: tristan <tristan@yuno.malio.fr>

frontend/stores/auth.ts

@@ -0,0 +1,58 @@
+import { defineStore } from 'pinia'
+import type { UserData } from '~/services/dto/user-data'
+import { getCurrentUser, login, logout } from '~/services/auth'
+
+export const useAuthStore = defineStore('auth', {
+  state: () => ({
+    user: null as UserData | null,
+    isLoading: false,
+    checked: false
+  }),
+  getters: {
+    isAuthenticated: (state) => Boolean(state.user)
+  },
+  actions: {
+    async ensureSession() {
+      if (this.checked) {
+        return this.user
+      }
+
+      this.checked = true
+
+      try {
+        const me = await getCurrentUser()
+        this.user = me
+        return me
+      } catch {
+        this.user = null
+        return null
+      }
+    },
+    async login(username: string, password: string) {
+      this.isLoading = true
+
+      try {
+        await login(username, password)
+        const me = await getCurrentUser()
+        this.user = me
+        this.checked = true
+        return me
+      } finally {
+        this.isLoading = false
+      }
+    },
+    async logout() {
+      this.isLoading = true
+
+      try {
+        await logout()
+      } catch {
+        // Ignore logout errors so we can still clear local auth state.
+      } finally {
+        this.user = null
+        this.checked = true
+        this.isLoading = false
+      }
+    }
+  }
+})