Multi-tenancy : espaces de travail + fix auth reload (rate limiter OPTIONS)

- Modèles Organization + OrgMember, migration Alembic (SQLite compatible)
- organization_id nullable sur Document, Decision, Mandate, VotingProtocol
- Service, schéma, router /organizations + dependency get_active_org_id
- Seed : Duniter G1 + Axiom Team ; tout le contenu seed attaché à Duniter G1
- Backend : list/create filtrés par header X-Organization
- Frontend : store organizations, WorkspaceSelector réel, useApi injecte l'org
- Fix critique : rate_limiter exclut les requêtes OPTIONS (CORS preflight)
  → résout le bug "Failed to fetch /auth/me" au reload (429 sur preflight)

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

frontend/app/pages/index.vue

@@ -116,6 +116,22 @@ function formatDate(dateStr: string): string {
       </p>
     </div>
 
+    <!-- Décider CTA -->
+    <NuxtLink to="/decisions/new" class="dash__decide">
+      <div class="dash__decide-left">
+        <div class="dash__decide-icon">
+          <UIcon name="i-lucide-scale" class="text-xl" />
+        </div>
+        <div class="dash__decide-text">
+          <span class="dash__decide-label">Prendre une décision</span>
+          <span class="dash__decide-sub">Individuelle · collective · déléguée — le parcours s'adapte</span>
+        </div>
+      </div>
+      <div class="dash__decide-arrow">
+        <UIcon name="i-lucide-arrow-right" class="text-base" />
+      </div>
+    </NuxtLink>
+
     <!-- Entry cards -->
     <div class="dash__entries">
       <template v-if="loading">
@@ -177,7 +193,7 @@ function formatDate(dateStr: string): string {
             <span class="dash__toolbox-card-tag">Vote WoT</span>
             <span class="dash__toolbox-card-tag">Inertie</span>
             <span class="dash__toolbox-card-tag">Smith</span>
-            <span class="dash__toolbox-card-tag">Nuancé</span>
+            <span class="dash__toolbox-card-tag">Élection</span>
           </div>
         </div>
         <UIcon name="i-lucide-arrow-right" class="dash__toolbox-card-arrow" />
@@ -292,6 +308,87 @@ function formatDate(dateStr: string): string {
   }
 }
 
+/* --- Décider CTA --- */
+.dash__decide {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 1rem;
+  padding: 1.25rem;
+  background: var(--mood-accent);
+  border-radius: 16px;
+  text-decoration: none;
+  transition: transform 0.12s ease, box-shadow 0.12s ease;
+}
+.dash__decide:hover {
+  transform: translateY(-2px);
+  box-shadow: 0 8px 28px var(--mood-shadow);
+}
+.dash__decide:active { transform: translateY(0); }
+
+.dash__decide-left {
+  display: flex;
+  align-items: center;
+  gap: 0.875rem;
+  min-width: 0;
+}
+
+.dash__decide-icon {
+  width: 2.75rem;
+  height: 2.75rem;
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  border-radius: 14px;
+  background: rgba(255,255,255,0.18);
+  color: var(--mood-accent-text);
+}
+
+.dash__decide-text {
+  display: flex;
+  flex-direction: column;
+  gap: 0.125rem;
+  min-width: 0;
+}
+
+.dash__decide-label {
+  font-size: 1rem;
+  font-weight: 800;
+  color: var(--mood-accent-text);
+  letter-spacing: -0.01em;
+}
+
+@media (min-width: 640px) {
+  .dash__decide-label { font-size: 1.125rem; }
+}
+
+.dash__decide-sub {
+  font-size: 0.75rem;
+  color: rgba(255,255,255,0.75);
+  font-weight: 500;
+}
+
+@media (min-width: 640px) {
+  .dash__decide-sub { font-size: 0.8125rem; }
+}
+
+.dash__decide-arrow {
+  flex-shrink: 0;
+  width: 2rem;
+  height: 2rem;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  border-radius: 50%;
+  background: rgba(255,255,255,0.18);
+  color: var(--mood-accent-text);
+  transition: transform 0.12s;
+}
+.dash__decide:hover .dash__decide-arrow {
+  transform: translateX(3px);
+}
+
 /* --- Entry cards --- */
 .dash__entries {
   display: grid;