[Spec Kit] Implementation progress

Implements all 88 tasks for the Reaction Image Board (specs/001-reaction-image-board):

- docker-compose.yml: postgres, minio, minio-init, api, ui services with healthchecks
- api/: FastAPI app with SQLAlchemy 2.x async, Alembic migrations, S3/MinIO storage,
  full integration + unit test suite (pytest + pytest-asyncio)
- ui/: Angular 19 standalone app (Library, Upload, Detail, NotFound components)
- .env.example: all required environment variables
- .gitignore: Python, Node, Docker, IDE, .env patterns

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/styles.css

@@ -0,0 +1,12 @@
+* {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+body {
+  font-family: system-ui, -apple-system, sans-serif;
+  background: #0f0f0f;
+  color: #e0e0e0;
+  min-height: 100vh;
+}