feat: Initial commit - Task Reporter incident response system

Complete implementation of the production line incident response system (生產線異常即時反應系統) including:

Backend (FastAPI):
- User authentication with AD integration and session management
- Chat room management (create, list, update, members, roles)
- Real-time messaging via WebSocket (typing indicators, reactions)
- File storage with MinIO (upload, download, image preview)

Frontend (React + Vite):
- Authentication flow with token management
- Room list with filtering, search, and pagination
- Real-time chat interface with WebSocket
- File upload with drag-and-drop and image preview
- Member management and room settings
- Breadcrumb navigation
- 53 unit tests (Vitest)

Specifications:
- authentication: AD auth, sessions, JWT tokens
- chat-room: rooms, members, templates
- realtime-messaging: WebSocket, messages, reactions
- file-storage: MinIO integration, file management
- frontend-core: React SPA structure

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

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

app/modules/file_storage/models.py

@@ -0,0 +1,44 @@
+"""Database models for file storage"""
+from sqlalchemy import Column, String, BigInteger, DateTime, Index, ForeignKey
+from sqlalchemy.orm import relationship
+from datetime import datetime
+from app.core.database import Base
+
+
+class RoomFile(Base):
+    """File uploaded to an incident room"""
+
+    __tablename__ = "room_files"
+
+    # Primary key
+    file_id = Column(String(36), primary_key=True)
+
+    # Foreign key to incident room
+    room_id = Column(String(36), ForeignKey("incident_rooms.room_id"), nullable=False)
+
+    # File metadata
+    uploader_id = Column(String(255), nullable=False)
+    filename = Column(String(255), nullable=False)
+    file_type = Column(String(20), nullable=False)  # 'image', 'document', 'log'
+    mime_type = Column(String(100), nullable=False)
+    file_size = Column(BigInteger, nullable=False)  # bytes
+
+    # MinIO storage information
+    minio_bucket = Column(String(100), nullable=False)
+    minio_object_path = Column(String(500), nullable=False)
+
+    # Timestamps
+    uploaded_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    deleted_at = Column(DateTime, nullable=True)  # soft delete
+
+    # Relationships
+    room = relationship("IncidentRoom", back_populates="files")
+
+    # Indexes
+    __table_args__ = (
+        Index("ix_room_files", "room_id", "uploaded_at"),
+        Index("ix_file_uploader", "uploader_id"),
+    )
+
+    def __repr__(self):
+        return f"<RoomFile(file_id={self.file_id}, filename={self.filename}, room_id={self.room_id})>"