feat: initialisation de ĞéoFlux — visualisation géographique Ğ1

- Carte Leaflet plein écran avec heatmap (OpenStreetMap, dark mode)
- Sélecteur de période 24h / 7j / 30j
- Panneau latéral : volume total, compteur de transactions, top 3 villes
- mockData.ts : 2 400 transactions simulées sur 24 villes FR/EU
- DataService.ts : abstraction prête pour branchement Subsquid/Ğ1v2
- Schémas Zod (g1.schema.ts) : validation runtime Duniter GVA + Cesium+
- Adaptateurs DuniterAdapter et CesiumAdapter (Ğ1v1, à migrer v2)
- Suite de tests Vitest : 43 tests, conformité schéma Ğ1 vérifiée

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

src/services/DataService.ts

@@ -0,0 +1,118 @@
+/**
+ * DataService — abstraction layer between the UI and data sources.
+ *
+ * Currently backed by mock data. To switch to the Subsquid GraphQL API:
+ *  1. Set `USE_LIVE_API = true` (or read from env: import.meta.env.VITE_USE_LIVE_API)
+ *  2. Fill in SUBSQUID_ENDPOINT with your indexer URL
+ *  3. Implement `fetchLiveTransactions` with a proper GraphQL query
+ */
+
+import {
+  getTransactionsForPeriod,
+  computeStats,
+  type Transaction,
+} from '../data/mockData';
+
+// ---------------------------------------------------------------------------
+// Configuration
+// ---------------------------------------------------------------------------
+const USE_LIVE_API = false;
+const SUBSQUID_ENDPOINT = 'https://squid.subsquid.io/g1-indexer/graphql'; // placeholder
+
+// ---------------------------------------------------------------------------
+// GraphQL helpers (used when USE_LIVE_API = true)
+// ---------------------------------------------------------------------------
+interface GqlTransactionEdge {
+  node: {
+    id: string;
+    blockTimestamp: string;
+    amount: string;
+    issuer: string;
+    recipient: string;
+    issuerlat?: number;
+    issuerlng?: number;
+    city?: string;
+  };
+}
+
+async function fetchLiveTransactions(periodDays: number): Promise<Transaction[]> {
+  const since = new Date(Date.now() - periodDays * 24 * 60 * 60 * 1000).toISOString();
+
+  const query = `
+    query GetTransactions($since: DateTime!) {
+      transfers(
+        where: { blockTimestamp_gte: $since }
+        orderBy: blockTimestamp_DESC
+        limit: 5000
+      ) {
+        edges {
+          node {
+            id
+            blockTimestamp
+            amount
+            issuer
+            recipient
+            issuerlat
+            issuerlng
+            city
+          }
+        }
+      }
+    }
+  `;
+
+  const response = await fetch(SUBSQUID_ENDPOINT, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ query, variables: { since } }),
+  });
+
+  if (!response.ok) {
+    throw new Error(`GraphQL request failed: ${response.statusText}`);
+  }
+
+  const { data, errors } = await response.json();
+  if (errors?.length) {
+    throw new Error(`GraphQL errors: ${JSON.stringify(errors)}`);
+  }
+
+  return (data.transfers.edges as GqlTransactionEdge[]).map((edge) => ({
+    id: edge.node.id,
+    timestamp: new Date(edge.node.blockTimestamp).getTime(),
+    lat: edge.node.issuerlat ?? 46.2276,  // fallback: France centroid
+    lng: edge.node.issuerlng ?? 2.2137,
+    amount: parseFloat(edge.node.amount) / 100, // Ğ1 uses centimes
+    city: edge.node.city ?? 'Inconnue',
+    fromKey: edge.node.issuer,
+    toKey: edge.node.recipient,
+  }));
+}
+
+// ---------------------------------------------------------------------------
+// Public API
+// ---------------------------------------------------------------------------
+export interface PeriodStats {
+  totalVolume: number;
+  transactionCount: number;
+  topCities: { name: string; volume: number; count: number }[];
+}
+
+export interface DataResult {
+  transactions: Transaction[];
+  stats: PeriodStats;
+}
+
+export async function fetchData(periodDays: number): Promise<DataResult> {
+  let transactions: Transaction[];
+
+  if (USE_LIVE_API) {
+    transactions = await fetchLiveTransactions(periodDays);
+  } else {
+    // Simulate async for drop-in replacement compatibility
+    await new Promise((r) => setTimeout(r, 120));
+    transactions = getTransactionsForPeriod(periodDays);
+  }
+
+  const stats = computeStats(transactions);
+  return { transactions, stats };
+}