# Plan 1 — Quick Wins & Low Risk

**Items covered:** #7 (updated_at bug), #8 (dead code), #9 (duplicate test file), #13 (unused dependency)

---

## Context

You are working on a FastAPI backend for a baby monitor / sleep tracker app. The codebase lives under `app/`. The task is to make four small, isolated fixes. Each one is mechanical and carries no risk of breaking behaviour. Do them in order. After each change, re-read the file you edited to verify it looks correct before moving on.

---

## Tasks

### 1. Fix the `updated_at` bug (`app/crud.py:106-113`)

The update handler in `crud.py` never sets `updated_at` after a PATCH/PUT. Find the update function and add the following line before the session is committed:

```python
session.updated_at = datetime.utcnow()
```

Make sure `datetime` is already imported; add the import if it is not.

### 2. Delete dead code

The following symbols are defined but never called anywhere. Delete them entirely:

- `ensure_aware()` — located in `app/crud.py:7-10`
- `minutes_after()` — located in `app/utils/time_utils.py:60-64`

After deleting each one, search the entire codebase (`grep -r "ensure_aware" .` and `grep -r "minutes_after" .`) to confirm nothing imports or calls the deleted symbol. If anything does, note it and do not delete the symbol — flag it for review instead.

Also locate `day_start_pattern()` in `app/utils/time_utils.py`. It is only used internally inside `get_day_night_splits()` in the same file. Rename it to `_day_start_pattern` (leading underscore) to mark it as a private helper and remove it from any `__all__` export list if present.

### 3. Delete the duplicate test file

`tests/test_sessions_fixed.py` is an exact copy of `tests/test_sessions.py`. Verify they are identical (or note any differences), then delete `tests/test_sessions_fixed.py`.

### 4. Remove the unused dependency

`python-multipart` is listed in `pyproject.toml` but is not used (the app has no `Form` parameters). Remove it:

```bash
uv remove python-multipart
```

If `uv` is not available, remove the line manually from `pyproject.toml` and run `uv sync` or the appropriate install command to update the lockfile.

---

## Verification

Run the full test suite after all changes:

```bash
pytest
```

All existing tests must pass. If any test fails, fix it before declaring this plan complete. Do not move on to Plan 2 until the test suite is green.