feat: animation temporelle des flux Ğ1

Nouveau mode animation accessible via "▶ Animer" dans le sélecteur de période.
- useAnimation : hook gérant frames, lecture, vitesse, filtrage client
- AnimationPlayer : barre de contrôle (play/pause, slider, ×1/×2/×4)
- Granularité auto : 24 frames/h (24h), 7 frames/jour (7j), ~4 frames/semaine (30j)
- Stats et heatmap mis à jour sur la fenêtre courante, zéro requête réseau supplémentaire

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

src/hooks/useAnimation.ts

@@ -0,0 +1,112 @@
+import { useState, useMemo, useEffect } from 'react';
+import type { Transaction } from '../data/mockData';
+
+export interface TimeFrame {
+  label: string;
+  from: number; // Unix ms
+  to: number;   // Unix ms
+}
+
+function buildFrames(periodDays: number): TimeFrame[] {
+  const now = Date.now();
+  const start = now - periodDays * 24 * 60 * 60 * 1000;
+
+  const fmt = (ms: number, opts: Intl.DateTimeFormatOptions) =>
+    new Date(ms).toLocaleDateString('fr-FR', opts);
+
+  if (periodDays === 1) {
+    return Array.from({ length: 24 }, (_, i) => {
+      const from = start + i * 3_600_000;
+      const to = from + 3_600_000;
+      const h = new Date(from).getHours();
+      return {
+        label: `${fmt(from, { weekday: 'short', day: 'numeric', month: 'short' })} · ${h}h – ${h + 1}h`,
+        from,
+        to,
+      };
+    });
+  }
+
+  if (periodDays === 7) {
+    return Array.from({ length: 7 }, (_, i) => {
+      const from = start + i * 86_400_000;
+      const to = from + 86_400_000;
+      return {
+        label: fmt(from, { weekday: 'long', day: 'numeric', month: 'short' }),
+        from,
+        to,
+      };
+    });
+  }
+
+  // 30 days → weekly frames
+  const frames: TimeFrame[] = [];
+  let cursor = start;
+  let week = 1;
+  while (cursor < now) {
+    const from = cursor;
+    const to = Math.min(cursor + 7 * 86_400_000, now);
+    frames.push({
+      label: `Semaine ${week} · ${fmt(from, { day: 'numeric', month: 'short' })} – ${fmt(to - 1, { day: 'numeric', month: 'short' })}`,
+      from,
+      to,
+    });
+    cursor = to;
+    week++;
+  }
+  return frames;
+}
+
+export function useAnimation(transactions: Transaction[], periodDays: number) {
+  const [active, setActive] = useState(false);
+  const [currentIndex, setCurrentIndex] = useState(0);
+  const [playing, setPlaying] = useState(false);
+  const [speed, setSpeed] = useState<1 | 2 | 4>(1);
+
+  const frames = useMemo(() => buildFrames(periodDays), [periodDays]);
+
+  // Reset cursor and playback when period or activation changes
+  useEffect(() => {
+    setCurrentIndex(0);
+    setPlaying(false);
+  }, [periodDays, active]);
+
+  // Auto-advance: one step every (2000 / speed) ms
+  useEffect(() => {
+    if (!playing || !active) return;
+    const delay = 2000 / speed;
+    const t = setTimeout(() => {
+      setCurrentIndex((i) => {
+        if (i >= frames.length - 1) {
+          setPlaying(false);
+          return i;
+        }
+        return i + 1;
+      });
+    }, delay);
+    return () => clearTimeout(t);
+  }, [playing, active, currentIndex, speed, frames.length]);
+
+  const visibleTransactions = useMemo(() => {
+    if (!active || frames.length === 0) return transactions;
+    const frame = frames[currentIndex];
+    if (!frame) return transactions;
+    return transactions.filter((t) => t.timestamp >= frame.from && t.timestamp < frame.to);
+  }, [active, transactions, frames, currentIndex]);
+
+  return {
+    active,
+    activate: () => setActive(true),
+    deactivate: () => { setActive(false); },
+    playing,
+    play: () => setPlaying(true),
+    pause: () => setPlaying(false),
+    currentIndex,
+    seek: (i: number) => { setCurrentIndex(i); setPlaying(false); },
+    speed,
+    setSpeed,
+    frames,
+    currentFrame: frames[currentIndex] ?? null,
+    visibleTransactions,
+  };
+}