feat: add FastAPI, Entity base class, and health check endpoint

.agent/current-plan.md

@@ -1,27 +1,18 @@
-# Plan: UserId Value Object
+# Plan: Add FastAPI to the Project
 
-## Status: COMPLETED
+## Goal
+Add FastAPI as the web framework with a minimal health check endpoint.
 
-## Objective
-Create a UserId value object in the marketplace domain with an immutable UUID value.
+## Changes
 
-## Decisions Made
-- **Location**: `domain/marketplace/user_id.py`
-- **Class style**: `@dataclass(frozen=True)` for immutability
-- **Tests**: Yes
+### 1. Dependencies
+- Add `fastapi` and `uvicorn[standard]` to `pyproject.toml` under `[project.dependencies]`
+- Install dependencies into the virtual environment
 
-## Value Object Structure
-```python
-@dataclass(frozen=True)
-class UserId:
-    value: UUID
-```
+### 2. Application Entry Point
+- Create `main.py` with a FastAPI app instance
+- Add a health check endpoint (`GET /`) that returns `{"status": "ok"}`
 
-## Files Created
-- `domain/marketplace/user_id.py`
-- `tests/test_user_id.py`
-
-## Test Results
-- `test_user_id_creation` - PASSED
-- `test_user_id_is_immutable` - PASSED
-- `test_user_id_equality` - PASSED
+## Verification
+- `pytest tests/` — all tests pass
+- `uvicorn main:app --reload` — server starts and health endpoint responds