feat: Phase 0 - Infrastructure and scaffolding (T-001 to T-003)

This commit establishes the foundational infrastructure for the Aegis
MITRE ATT&CK Coverage Platform.

T-001: Initialize project and Docker Compose
- Set up Docker Compose with PostgreSQL 15, MinIO, and FastAPI backend
- Create basic FastAPI application with health endpoint
- Configure persistent volumes for data storage

T-002: Configuration and database connection
- Add centralized configuration using pydantic-settings
- Implement SQLAlchemy database connection with session management
- Configure MinIO and JWT settings

T-003: Initialize Alembic for migrations
- Set up Alembic with PostgreSQL connection from settings
- Create initial empty migration
- Configure autogenerate support for future models

Also includes:
- Professional README with setup instructions
- Comprehensive .gitignore for Python/Node/Docker
- Project task plan (AegisTestPlan.md)

docker-compose.yml

@@ -0,0 +1,40 @@
+services:
+  postgres:
+    image: postgres:15
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: attackdb
+    ports:
+      - "5433:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+
+  minio:
+    image: minio/minio
+    command: server /data --console-address ":9001"
+    environment:
+      MINIO_ROOT_USER: minioadmin
+      MINIO_ROOT_PASSWORD: minioadmin
+    ports:
+      - "9000:9000"
+      - "9001:9001"
+    volumes:
+      - minio_data:/data
+
+  backend:
+    build: ./backend
+    ports:
+      - "8000:8000"
+    environment:
+      DATABASE_URL: postgresql://postgres:postgres@postgres:5432/attackdb
+    depends_on:
+      - postgres
+      - minio
+    command: uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload
+    volumes:
+      - ./backend:/app
+
+volumes:
+  postgres_data:
+  minio_data: