Sprint 4 : decisions et mandats -- workflow complet + vote integration

Backend: 7 nouveaux endpoints (advance, assign, revoke, create-vote-session),
services enrichis avec creation de sessions de vote, assignation de mandataire
et revocation. 35 nouveaux tests (104 total). Frontend: store mandates, page
cadrage decisions, detail mandats, composants DecisionWorkflow, DecisionCadrage,
DecisionCard, MandateTimeline, MandateCard. Documentation mise a jour.

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

frontend/app/components/decisions/DecisionCard.vue

@@ -0,0 +1,71 @@
+<script setup lang="ts">
+/**
+ * Card component for displaying a decision in a list.
+ *
+ * Shows title, type badge, status badge, step count, and creation date.
+ * Navigates to the decision detail page on click.
+ */
+import type { Decision } from '~/stores/decisions'
+
+const props = defineProps<{
+  decision: Decision
+}>()
+
+const typeLabel = (decisionType: string) => {
+  switch (decisionType) {
+    case 'runtime_upgrade': return 'Runtime upgrade'
+    case 'document_change': return 'Modif. document'
+    case 'mandate_vote': return 'Vote de mandat'
+    case 'parameter_change': return 'Param. change'
+    case 'other': return 'Autre'
+    default: return decisionType
+  }
+}
+
+function formatDate(dateStr: string): string {
+  return new Date(dateStr).toLocaleDateString('fr-FR', {
+    day: 'numeric',
+    month: 'short',
+    year: 'numeric',
+  })
+}
+
+function navigate() {
+  navigateTo(`/decisions/${props.decision.id}`)
+}
+</script>
+
+<template>
+  <UCard
+    class="cursor-pointer hover:ring-2 hover:ring-primary/50 hover:shadow-md transition-all"
+    @click="navigate"
+  >
+    <div class="space-y-3">
+      <div class="flex items-start justify-between">
+        <div class="flex items-center gap-2">
+          <UIcon name="i-lucide-scale" class="text-gray-400" />
+          <h3 class="font-semibold text-gray-900 dark:text-white">
+            {{ decision.title }}
+          </h3>
+        </div>
+        <CommonStatusBadge :status="decision.status" type="decision" />
+      </div>
+
+      <p v-if="decision.description" class="text-sm text-gray-600 dark:text-gray-400 line-clamp-2">
+        {{ decision.description }}
+      </p>
+
+      <div class="flex items-center gap-3 flex-wrap">
+        <UBadge variant="subtle" color="primary" size="xs">
+          {{ typeLabel(decision.decision_type) }}
+        </UBadge>
+        <span class="text-xs text-gray-500">
+          {{ decision.steps.length }} etape(s)
+        </span>
+        <span class="text-xs text-gray-500">
+          {{ formatDate(decision.created_at) }}
+        </span>
+      </div>
+    </div>
+  </UCard>
+</template>