feat(storage): add MinIO local storage and @manacore/shared-storage package

- Add MinIO service to docker-compose.dev.yml with auto-bucket initialization
- Create @manacore/shared-storage package with S3-compatible client
- Add factory functions for each project (Picture, Chat, ManaDeck, etc.)
- Include file utilities (generateFileKey, getContentType, validators)
- Update environment variables for S3/MinIO configuration
- Document storage architecture in CLAUDE.md

Local dev uses MinIO, production will use Hetzner Object Storage.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

packages/shared-storage/src/utils.ts

@@ -0,0 +1,135 @@
+import { randomUUID } from 'crypto';
+import { extname } from 'path';
+
+/**
+ * Generate a unique file key with optional folder structure
+ *
+ * @example
+ * generateFileKey('image.png', 'user-123')
+ * // => 'user-123/a1b2c3d4-e5f6-7890-abcd-ef1234567890.png'
+ *
+ * generateFileKey('photo.jpg', 'users', 'avatars')
+ * // => 'users/avatars/a1b2c3d4-e5f6-7890-abcd-ef1234567890.jpg'
+ */
+export function generateFileKey(filename: string, ...folders: string[]): string {
+	const ext = extname(filename);
+	const uuid = randomUUID();
+	const key = `${uuid}${ext}`;
+
+	if (folders.length > 0) {
+		return [...folders, key].join('/');
+	}
+
+	return key;
+}
+
+/**
+ * Generate a user-scoped file key
+ *
+ * @example
+ * generateUserFileKey('user-123', 'avatar.png')
+ * // => 'users/user-123/a1b2c3d4-e5f6-7890-abcd-ef1234567890.png'
+ */
+export function generateUserFileKey(userId: string, filename: string, subfolder?: string): string {
+	const folders = subfolder ? ['users', userId, subfolder] : ['users', userId];
+	return generateFileKey(filename, ...folders);
+}
+
+/**
+ * Get content type from filename extension
+ */
+export function getContentType(filename: string): string {
+	const ext = extname(filename).toLowerCase();
+
+	const mimeTypes: Record<string, string> = {
+		// Images
+		'.jpg': 'image/jpeg',
+		'.jpeg': 'image/jpeg',
+		'.png': 'image/png',
+		'.gif': 'image/gif',
+		'.webp': 'image/webp',
+		'.svg': 'image/svg+xml',
+		'.ico': 'image/x-icon',
+		'.avif': 'image/avif',
+
+		// Documents
+		'.pdf': 'application/pdf',
+		'.doc': 'application/msword',
+		'.docx': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+		'.xls': 'application/vnd.ms-excel',
+		'.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+		'.ppt': 'application/vnd.ms-powerpoint',
+		'.pptx': 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+
+		// Text
+		'.txt': 'text/plain',
+		'.csv': 'text/csv',
+		'.json': 'application/json',
+		'.xml': 'application/xml',
+		'.html': 'text/html',
+		'.css': 'text/css',
+		'.js': 'application/javascript',
+
+		// Audio
+		'.mp3': 'audio/mpeg',
+		'.wav': 'audio/wav',
+		'.ogg': 'audio/ogg',
+		'.m4a': 'audio/mp4',
+
+		// Video
+		'.mp4': 'video/mp4',
+		'.webm': 'video/webm',
+		'.mov': 'video/quicktime',
+		'.avi': 'video/x-msvideo',
+
+		// Archives
+		'.zip': 'application/zip',
+		'.tar': 'application/x-tar',
+		'.gz': 'application/gzip',
+		'.rar': 'application/vnd.rar',
+
+		// Other
+		'.woff': 'font/woff',
+		'.woff2': 'font/woff2',
+		'.ttf': 'font/ttf',
+		'.otf': 'font/otf',
+	};
+
+	return mimeTypes[ext] ?? 'application/octet-stream';
+}
+
+/**
+ * Validate file size
+ */
+export function validateFileSize(sizeInBytes: number, maxSizeMB: number): boolean {
+	const maxSizeBytes = maxSizeMB * 1024 * 1024;
+	return sizeInBytes <= maxSizeBytes;
+}
+
+/**
+ * Validate file extension
+ */
+export function validateFileExtension(filename: string, allowedExtensions: string[]): boolean {
+	const ext = extname(filename).toLowerCase();
+	return allowedExtensions.includes(ext);
+}
+
+/**
+ * Common allowed extensions for images
+ */
+export const IMAGE_EXTENSIONS = ['.jpg', '.jpeg', '.png', '.gif', '.webp', '.svg', '.avif'];
+
+/**
+ * Common allowed extensions for documents
+ */
+export const DOCUMENT_EXTENSIONS = ['.pdf', '.doc', '.docx', '.xls', '.xlsx', '.ppt', '.pptx'];
+
+/**
+ * Common allowed extensions for audio
+ */
+export const AUDIO_EXTENSIONS = ['.mp3', '.wav', '.ogg', '.m4a'];
+
+/**
+ * Common allowed extensions for video
+ */
+export const VIDEO_EXTENSIONS = ['.mp4', '.webm', '.mov', '.avi'];