Renomme excalidraw-go en excalicloud

Module Go github.com/vblogio/excalicloud (imports internes mis à jour),
image Docker excalicloud:local, paquet npm excalicloud-frontend,
champ source des exports .excalidraw, README et THIRD_PARTY_NOTICES.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019MgtkAhkuqFbMAuTgTDeFh

internal/mcp/tools.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/vblogio/excalidraw-go/internal/storage"
+	"github.com/vblogio/excalicloud/internal/storage"
 )
 
 const instructions = `Excalicloud stocke des schémas Excalidraw (.excalidraw) dans une arborescence de dossiers partagée entre les utilisateurs.