feat: rename keep-notes to memento-note, migrate to PostgreSQL, fix MCP bugs

- Rename directory keep-notes -> memento-note with all code references
- Prisma: SQLite -> PostgreSQL (both app and MCP server schemas)
- Sync MCP schema with main app (add missing fields, relations, indexes)
- Delete 17 SQLite migrations (clean slate for PostgreSQL)
- Remove SQLite dependencies (@libsql/client, better-sqlite3, etc.)
- Fix MCP server: hardcoded Windows DB paths -> DATABASE_URL env var
- Fix MCP server: .dockerignore excluded index-sse.js (SSE mode broken)
- MCP Dockerfile: node:20 -> node:22
- Docker Compose: add postgres service, remove SQLite volume
- Generate favicon.ico, icon-192.png, icon-512.png, apple-icon.png
- Update layout.tsx icons and manifest.json for PNG icons
- Update all .env files for PostgreSQL
- Rewrite README.md with updated sections
- Remove mcp-server/node_modules and prisma/client-generated from git tracking

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

memento-note/components/collaborator-avatars.tsx

@@ -0,0 +1,73 @@
+'use client'
+
+import { Avatar, AvatarFallback, AvatarImage } from '@/components/ui/avatar'
+import { Badge } from '@/components/ui/badge'
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip'
+import { useLanguage } from '@/lib/i18n'
+
+interface Collaborator {
+  id: string
+  name: string | null
+  email: string
+  image: string | null
+}
+
+interface CollaboratorAvatarsProps {
+  collaborators: Collaborator[]
+  ownerId: string
+  maxDisplay?: number
+}
+
+export function CollaboratorAvatars({ collaborators, ownerId, maxDisplay = 5 }: CollaboratorAvatarsProps) {
+  const { t } = useLanguage()
+
+  if (collaborators.length === 0) return null
+
+  const displayCollaborators = collaborators.slice(0, maxDisplay)
+  const remainingCount = collaborators.length - maxDisplay
+
+  return (
+    <div className="flex items-center gap-1 mt-2">
+      <TooltipProvider>
+        {displayCollaborators.map((collaborator) => (
+          <Tooltip key={collaborator.id}>
+            <TooltipTrigger asChild>
+              <div className="relative group">
+                <Avatar className="h-6 w-6 border-2 border-background">
+                  <AvatarImage src={collaborator.image || undefined} />
+                  <AvatarFallback className="text-xs">
+                    {collaborator.name?.charAt(0).toUpperCase() || collaborator.email.charAt(0).toUpperCase()}
+                  </AvatarFallback>
+                </Avatar>
+                {collaborator.id === ownerId && (
+                  <div className="absolute -bottom-1 -right-1">
+                    <Badge variant="secondary" className="text-[8px] h-3 px-1 min-w-0">
+                      {t('collaboration.owner')}
+                    </Badge>
+                  </div>
+                )}
+              </div>
+            </TooltipTrigger>
+            <TooltipContent>
+              <p className="font-medium">{collaborator.name || t('collaboration.unnamedUser')}</p>
+              <p className="text-xs text-muted-foreground">{collaborator.email}</p>
+            </TooltipContent>
+          </Tooltip>
+        ))}
+
+        {remainingCount > 0 && (
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <div className="h-6 w-6 rounded-full bg-muted flex items-center justify-center text-xs border-2 border-background">
+                +{remainingCount}
+              </div>
+            </TooltipTrigger>
+            <TooltipContent>
+              <p>{remainingCount} {t('collaboration.canEdit')}</p>
+            </TooltipContent>
+          </Tooltip>
+        )}
+      </TooltipProvider>
+    </div>
+  )
+}