Groupes d'identités : modèle DB, router, store, UI cercles + Protocoles

- Group + GroupMember : modèle SQLAlchemy + migration + router CRUD
- /api/v1/groups : liste, création, suppression, membres (add/remove)
- groups.ts : store Pinia (fetchAll, getGroup, create, remove, addMember, removeMember)
- decisions/new.vue : cercles 1 & 2 en mode texte libre OU groupe prédéfini
  (affected_count calculé depuis le member_count du groupe)
- protocols/index.vue : section Groupes avec expand/collapse, ajout/suppression membres
- lang="fr" + spellcheck sur tous les textareas ; placeholder cercle 2 corrigé
- n8n channels : prévu sprint futur (texte libre → webhook appel à contribution)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/app/stores/groups.ts

@@ -0,0 +1,110 @@
+export interface GroupMember {
+  id: string
+  display_name: string
+  identity_id: string | null
+  added_at: string
+}
+
+export interface Group {
+  id: string
+  name: string
+  description: string | null
+  organization_id: string | null
+  created_at: string
+  members: GroupMember[]
+}
+
+export interface GroupSummary {
+  id: string
+  name: string
+  description: string | null
+  organization_id: string | null
+  member_count: number
+}
+
+export interface GroupCreate {
+  name: string
+  description?: string | null
+}
+
+export interface GroupMemberCreate {
+  display_name: string
+  identity_id?: string | null
+}
+
+export const useGroupsStore = defineStore('groups', () => {
+  const { $api } = useApi()
+  const orgs = useOrgsStore()
+
+  const list = ref<GroupSummary[]>([])
+  const loading = ref(false)
+  const error = ref<string | null>(null)
+
+  async function fetchAll() {
+    loading.value = true
+    error.value = null
+    try {
+      list.value = await $api<GroupSummary[]>('/groups/')
+    } catch (e: any) {
+      error.value = e?.message ?? 'Erreur chargement groupes'
+    } finally {
+      loading.value = false
+    }
+  }
+
+  async function getGroup(id: string): Promise<Group | null> {
+    try {
+      return await $api<Group>(`/groups/${id}`)
+    } catch {
+      return null
+    }
+  }
+
+  async function create(payload: GroupCreate): Promise<Group | null> {
+    try {
+      const group = await $api<Group>('/groups/', { method: 'POST', body: payload })
+      await fetchAll()
+      return group
+    } catch (e: any) {
+      error.value = e?.message ?? 'Erreur création groupe'
+      return null
+    }
+  }
+
+  async function remove(id: string): Promise<boolean> {
+    try {
+      await $api(`/groups/${id}`, { method: 'DELETE' })
+      list.value = list.value.filter(g => g.id !== id)
+      return true
+    } catch {
+      return false
+    }
+  }
+
+  async function addMember(groupId: string, payload: GroupMemberCreate): Promise<GroupMember | null> {
+    try {
+      const member = await $api<GroupMember>(`/groups/${groupId}/members`, {
+        method: 'POST',
+        body: payload,
+      })
+      const g = list.value.find(g => g.id === groupId)
+      if (g) g.member_count++
+      return member
+    } catch {
+      return null
+    }
+  }
+
+  async function removeMember(groupId: string, memberId: string): Promise<boolean> {
+    try {
+      await $api(`/groups/${groupId}/members/${memberId}`, { method: 'DELETE' })
+      const g = list.value.find(g => g.id === groupId)
+      if (g) g.member_count--
+      return true
+    } catch {
+      return false
+    }
+  }
+
+  return { list, loading, error, fetchAll, getGroup, create, remove, addMember, removeMember }
+})