feat(gif-mood): drag-and-drop reorder + note footer centering

- Add drag-and-drop reordering (dnd-kit/sortable) for current user's GIFs with optimistic updates
- Add reorderGifMoodItems service + action with SSE broadcast
- Fix item sort order: orderBy order asc instead of createdAt
- Note footer: auto-resize textarea, vertically centered (1 or 2 lines), default 4 columns

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

src/actions/gif-mood.ts

@@ -228,6 +228,45 @@ export async function deleteGifMoodItem(sessionId: string, itemId: string) {
   }
 }
 
+export async function reorderGifMoodItems(sessionId: string, orderedIds: string[]) {
+  const authSession = await auth();
+  if (!authSession?.user?.id) {
+    return { success: false, error: 'Non autorisé' };
+  }
+
+  const canEdit = await gifMoodService.canEditGifMoodSession(sessionId, authSession.user.id);
+  if (!canEdit) {
+    return { success: false, error: 'Permission refusée' };
+  }
+
+  try {
+    await gifMoodService.reorderGifMoodItems(sessionId, authSession.user.id, orderedIds);
+
+    const user = await getUserById(authSession.user.id);
+    if (user) {
+      const event = await gifMoodService.createGifMoodSessionEvent(
+        sessionId,
+        authSession.user.id,
+        'GIF_UPDATED',
+        { orderedIds }
+      );
+      broadcastToGifMoodSession(sessionId, {
+        type: 'GIF_UPDATED',
+        payload: { orderedIds },
+        userId: authSession.user.id,
+        user: { id: user.id, name: user.name, email: user.email },
+        timestamp: event.createdAt,
+      });
+    }
+
+    revalidatePath(`/gif-mood/${sessionId}`);
+    return { success: true };
+  } catch (error) {
+    console.error('Error reordering gif mood items:', error);
+    return { success: false, error: 'Erreur lors de la réorganisation' };
+  }
+}
+
 // ============================================
 // Week Rating Actions
 // ============================================

src/components/gif-mood/GifMoodBoard.tsx

@@ -1,7 +1,22 @@
 'use client';
 
 import { useMemo, useState, useTransition } from 'react';
-import { setGifMoodUserRating } from '@/actions/gif-mood';
+import {
+  DndContext,
+  closestCenter,
+  PointerSensor,
+  useSensor,
+  useSensors,
+  type DragEndEvent,
+} from '@dnd-kit/core';
+import {
+  SortableContext,
+  rectSortingStrategy,
+  useSortable,
+  arrayMove,
+} from '@dnd-kit/sortable';
+import { CSS } from '@dnd-kit/utilities';
+import { setGifMoodUserRating, reorderGifMoodItems } from '@/actions/gif-mood';
 import { Avatar } from '@/components/ui/Avatar';
 import { GifMoodCard } from './GifMoodCard';
 import { GifMoodAddForm } from './GifMoodAddForm';
@@ -115,6 +130,57 @@ function WeekRating({
   );
 }
 
+function DragHandle(props: React.HTMLAttributes<HTMLDivElement>) {
+  return (
+    <div
+      {...props}
+      className="absolute top-2 left-2 z-10 p-1.5 rounded-full bg-black/50 text-white opacity-0 group-hover/card:opacity-100 cursor-grab active:cursor-grabbing backdrop-blur-sm transition-opacity"
+      title="Réorganiser"
+    >
+      <svg width="12" height="12" viewBox="0 0 12 12" fill="currentColor" aria-hidden>
+        <circle cx="4" cy="2.5" r="1.2" />
+        <circle cx="8" cy="2.5" r="1.2" />
+        <circle cx="4" cy="6" r="1.2" />
+        <circle cx="8" cy="6" r="1.2" />
+        <circle cx="4" cy="9.5" r="1.2" />
+        <circle cx="8" cy="9.5" r="1.2" />
+      </svg>
+    </div>
+  );
+}
+
+function SortableGifMoodCard({
+  sessionId,
+  item,
+  currentUserId,
+  canEdit,
+}: {
+  sessionId: string;
+  item: GifMoodItem;
+  currentUserId: string;
+  canEdit: boolean;
+}) {
+  const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({
+    id: item.id,
+  });
+
+  return (
+    <div
+      ref={setNodeRef}
+      style={{ transform: CSS.Transform.toString(transform), transition }}
+      className={`group/card relative ${isDragging ? 'opacity-50 z-50' : ''}`}
+    >
+      <DragHandle {...attributes} {...listeners} />
+      <GifMoodCard
+        sessionId={sessionId}
+        item={item}
+        currentUserId={currentUserId}
+        canEdit={canEdit}
+      />
+    </div>
+  );
+}
+
 // Subtle accent colors for each user section
 const SECTION_COLORS = ['#ec4899', '#8b5cf6', '#3b82f6', '#10b981', '#f59e0b', '#ef4444'];
 
@@ -150,7 +216,20 @@ export function GifMoodBoard({
   ratings,
   canEdit,
 }: GifMoodBoardProps) {
-  const [cols, setCols] = useState(5);
+  const [cols, setCols] = useState(4);
+  const [, startReorderTransition] = useTransition();
+
+  // Optimistic reorder state for the current user's items
+  const [optimisticItems, setOptimisticItems] = useState<GifMoodItem[]>([]);
+  const [prevPropsItems, setPrevPropsItems] = useState(items);
+  if (prevPropsItems !== items) {
+    setPrevPropsItems(items);
+    setOptimisticItems([]);
+  }
+
+  const sensors = useSensors(
+    useSensor(PointerSensor, { activationConstraint: { distance: 5 } })
+  );
 
   const allUsers = useMemo(() => {
     const map = new Map<string, { id: string; name: string | null; email: string }>();
@@ -179,6 +258,24 @@ export function GifMoodBoard({
     });
   }, [allUsers, currentUserId, owner.id]);
 
+  function handleDragEnd(event: DragEndEvent) {
+    const { active, over } = event;
+    if (!over || active.id === over.id) return;
+
+    const currentItems =
+      optimisticItems.length > 0 ? optimisticItems : (itemsByUser.get(currentUserId) ?? []);
+    const oldIndex = currentItems.findIndex((i) => i.id === active.id);
+    const newIndex = currentItems.findIndex((i) => i.id === over.id);
+    if (oldIndex === -1 || newIndex === -1) return;
+
+    const reordered = arrayMove(currentItems, oldIndex, newIndex);
+    setOptimisticItems(reordered);
+
+    startReorderTransition(async () => {
+      await reorderGifMoodItems(sessionId, reordered.map((i) => i.id));
+    });
+  }
+
   return (
     <div className="space-y-10">
       {/* Column size control */}
@@ -201,8 +298,10 @@ export function GifMoodBoard({
         </div>
       </div>
       {sortedUsers.map((user, index) => {
-        const userItems = itemsByUser.get(user.id) ?? [];
         const isCurrentUser = user.id === currentUserId;
+        const serverItems = itemsByUser.get(user.id) ?? [];
+        const userItems =
+          isCurrentUser && optimisticItems.length > 0 ? optimisticItems : serverItems;
         const canAdd = canEdit && isCurrentUser && userItems.length < GIF_MOOD_MAX_ITEMS;
         const accentColor = SECTION_COLORS[index % SECTION_COLORS.length];
         const userRating = ratings.find((r) => r.userId === user.id)?.rating ?? null;
@@ -242,6 +341,38 @@ export function GifMoodBoard({
             </div>
 
             {/* Grid */}
+            {isCurrentUser && canEdit ? (
+              <DndContext
+                sensors={sensors}
+                collisionDetection={closestCenter}
+                onDragEnd={handleDragEnd}
+              >
+                <SortableContext
+                  items={userItems.map((i) => i.id)}
+                  strategy={rectSortingStrategy}
+                >
+                  <div className={`grid ${GRID_COLS[cols]} gap-4 items-start`}>
+                    {userItems.map((item) => (
+                      <SortableGifMoodCard
+                        key={item.id}
+                        sessionId={sessionId}
+                        item={item}
+                        currentUserId={currentUserId}
+                        canEdit={canEdit}
+                      />
+                    ))}
+                    {canAdd && (
+                      <GifMoodAddForm sessionId={sessionId} currentCount={userItems.length} />
+                    )}
+                    {!canAdd && userItems.length === 0 && (
+                      <div className="col-span-full flex items-center justify-center rounded-2xl border border-dashed border-border/60 py-10">
+                        <p className="text-sm text-muted/60">Aucun GIF pour le moment</p>
+                      </div>
+                    )}
+                  </div>
+                </SortableContext>
+              </DndContext>
+            ) : (
               <div className={`grid ${GRID_COLS[cols]} gap-4 items-start`}>
                 {userItems.map((item) => (
                   <GifMoodCard
@@ -252,19 +383,13 @@ export function GifMoodBoard({
                     canEdit={canEdit}
                   />
                 ))}
-
-              {/* Add form slot */}
-              {canAdd && (
-                <GifMoodAddForm sessionId={sessionId} currentCount={userItems.length} />
-              )}
-
-              {/* Empty state */}
                 {!canAdd && userItems.length === 0 && (
                   <div className="col-span-full flex items-center justify-center rounded-2xl border border-dashed border-border/60 py-10">
                     <p className="text-sm text-muted/60">Aucun GIF pour le moment</p>
                   </div>
                 )}
               </div>
+            )}
           </section>
         );
       })}

src/components/gif-mood/GifMoodCard.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { memo, useState, useTransition } from 'react';
+import { memo, useRef, useEffect, useState, useTransition } from 'react';
 import { updateGifMoodItem, deleteGifMoodItem } from '@/actions/gif-mood';
 import { IconClose } from '@/components/ui';
 
@@ -26,6 +26,14 @@ export const GifMoodCard = memo(function GifMoodCard({
   const [itemVersion, setItemVersion] = useState(item);
   const [isPending, startTransition] = useTransition();
   const [imgError, setImgError] = useState(false);
+  const textareaRef = useRef<HTMLTextAreaElement>(null);
+
+  useEffect(() => {
+    const el = textareaRef.current;
+    if (!el) return;
+    el.style.height = 'auto';
+    el.style.height = el.scrollHeight + 'px';
+  }, [note]);
 
   if (itemVersion !== item) {
     setItemVersion(item);
@@ -90,20 +98,21 @@ export const GifMoodCard = memo(function GifMoodCard({
 
       {/* Note */}
       {canEditThis ? (
-        <div className="px-3 pt-2 pb-3 bg-card">
+        <div className="px-3 bg-card flex items-center justify-center min-h-[2.75rem]">
           <textarea
+            ref={textareaRef}
             value={note}
             onChange={(e) => setNote(e.target.value)}
             onBlur={handleNoteBlur}
             placeholder="Ajouter une note…"
             rows={1}
-            className="w-full text-foreground/70 bg-transparent resize-none outline-none placeholder:text-muted/40 leading-relaxed text-center"
+            className="w-full text-foreground/70 bg-transparent resize-none outline-none placeholder:text-muted/40 leading-snug text-center overflow-hidden"
-            style={{ fontFamily: 'var(--font-caveat)', fontSize: '1.2rem' }}
+            style={{ fontFamily: 'var(--font-caveat)', fontSize: '1rem' }}
           />
         </div>
       ) : note ? (
-        <div className="px-3 py-2.5 bg-card">
+        <div className="px-3 bg-card flex items-center justify-center min-h-[2.75rem]">
-          <p className="text-foreground/70 leading-relaxed text-center" style={{ fontFamily: 'var(--font-caveat)', fontSize: '1.2rem' }}>{note}</p>
+          <p className="text-foreground/70 leading-snug text-center" style={{ fontFamily: 'var(--font-caveat)', fontSize: '1rem' }}>{note}</p>
         </div>
       ) : null}
     </div>

src/services/gif-mood.ts

@@ -66,7 +66,7 @@ const gifMoodByIdInclude = {
   user: { select: { id: true, name: true, email: true } },
   items: {
     include: { user: { select: { id: true, name: true, email: true } } },
-    orderBy: { createdAt: 'asc' as const },
+    orderBy: { order: 'asc' as const },
   },
   shares: { include: { user: { select: { id: true, name: true, email: true } } } },
   ratings: { select: { userId: true, rating: true } },
@@ -186,6 +186,21 @@ export async function deleteGifMoodItem(itemId: string, userId: string) {
   });
 }
 
+export async function reorderGifMoodItems(
+  sessionId: string,
+  userId: string,
+  orderedIds: string[]
+) {
+  return prisma.$transaction(
+    orderedIds.map((id, index) =>
+      prisma.gifMoodItem.updateMany({
+        where: { id, userId, sessionId },
+        data: { order: index },
+      })
+    )
+  );
+}
+
 export async function upsertGifMoodUserRating(
   sessionId: string,
   userId: string,