feat: Implement Step 12 - File System with MinIO S3 Storage

Completed File Management Service with S3-compatible object storage:

Infrastructure:
- Added MinIO for S3-compatible object storage (port 9000/9001)
- Integrated with MongoDB for metadata management
- Configured Docker volumes for persistent storage

File Service Features:
- Multi-file upload support with deduplication
- Automatic thumbnail generation for images (multiple sizes)
- File metadata management with search and filtering
- Presigned URLs for secure direct uploads/downloads
- Public/private file access control
- Large file upload support with chunking
- File type detection and categorization

API Endpoints:
- File upload (single and multiple)
- File retrieval with metadata
- Thumbnail generation and caching
- Storage statistics and analytics
- Bucket management
- Batch operations support

Technical Improvements:
- Fixed Pydantic v2.5 compatibility (regex -> pattern)
- Optimized thumbnail caching strategy
- Implemented file hash-based deduplication

Testing:
- All services health checks passing
- MinIO and file service fully operational
- Ready for production use

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

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

services/files/backend/models.py

@@ -0,0 +1,112 @@
+"""
+Data models for File Management Service
+"""
+from pydantic import BaseModel, Field
+from datetime import datetime
+from typing import Optional, List, Dict, Any
+from enum import Enum
+
+class FileType(str, Enum):
+    IMAGE = "image"
+    VIDEO = "video"
+    AUDIO = "audio"
+    DOCUMENT = "document"
+    ARCHIVE = "archive"
+    OTHER = "other"
+
+class FileStatus(str, Enum):
+    PENDING = "pending"
+    PROCESSING = "processing"
+    READY = "ready"
+    ERROR = "error"
+    DELETED = "deleted"
+
+class FileMetadata(BaseModel):
+    id: str
+    filename: str
+    original_name: str
+    size: int
+    content_type: str
+    file_type: FileType
+    bucket: str
+    object_name: str
+    user_id: str
+    hash: str
+    status: FileStatus = FileStatus.READY
+    public: bool = False
+    has_thumbnail: bool = False
+    thumbnail_url: Optional[str] = None
+    tags: Dict[str, Any] = {}
+    metadata: Dict[str, Any] = {}
+    download_count: int = 0
+    created_at: datetime
+    updated_at: datetime
+    deleted_at: Optional[datetime] = None
+
+class FileUploadResponse(BaseModel):
+    file_id: str
+    filename: str
+    size: int
+    content_type: str
+    file_type: FileType
+    bucket: str
+    public: bool
+    has_thumbnail: bool
+    thumbnail_url: Optional[str] = None
+    download_url: Optional[str] = None
+    created_at: datetime
+    message: str = "File uploaded successfully"
+
+class FileListResponse(BaseModel):
+    files: List[FileMetadata]
+    total: int
+    limit: int
+    offset: int
+    has_more: bool
+
+class StorageStats(BaseModel):
+    total_files: int
+    total_size: int
+    buckets: List[str]
+    users_count: int
+    file_types: Dict[str, int]
+    storage_used_percentage: Optional[float] = None
+    
+class ThumbnailRequest(BaseModel):
+    file_id: str
+    width: int = Field(200, ge=50, le=1000)
+    height: int = Field(200, ge=50, le=1000)
+    quality: int = Field(85, ge=50, le=100)
+    format: str = Field("jpeg", pattern="^(jpeg|png|webp)$")
+
+class PresignedUrlResponse(BaseModel):
+    url: str
+    expires_in: int
+    method: str
+    headers: Optional[Dict[str, str]] = None
+
+class BatchOperationResult(BaseModel):
+    successful: List[str]
+    failed: List[Dict[str, str]]
+    total_processed: int
+    total_successful: int
+    total_failed: int
+
+class FileShareLink(BaseModel):
+    share_url: str
+    expires_in: int
+    file_id: str
+    filename: str
+    created_at: datetime
+    expires_at: datetime
+
+class FileProcessingJob(BaseModel):
+    job_id: str
+    file_id: str
+    job_type: str  # thumbnail, compress, convert, etc.
+    status: str  # pending, processing, completed, failed
+    progress: Optional[float] = None
+    result: Optional[Dict[str, Any]] = None
+    error: Optional[str] = None
+    created_at: datetime
+    completed_at: Optional[datetime] = None