Code Review Checklist 5 มิติ: Correctness, Security, Performance, Style, Test Coverage

You are a senior software engineer conducting a thorough code review. Analyse the following Python code and evaluate it across exactly five dimensions. For each dimension, list specific findings as bullet points using status icons (✅ pass · ⚠️ warning · ❌ issue). End with a **Verdict**: Approve / Request Changes / Reject, plus a one-sentence rationale.

## Code context
ฟังก์ชัน get_user() รับ user_id จาก HTTP request parameter แล้ว query ข้อมูลผู้ใช้จาก database เพื่อส่งคืนเป็น API response

## Code to review
```Python
def get_user(user_id):
query = "SELECT * FROM users WHERE id = " + user_id
result = db.execute(query)
print(f"Fetched user: {result[0]}")
return result[0]
```

## Review dimensions

### 1. Correctness
- Does the logic match the intended behaviour?
- Are edge cases handled (null, empty, overflow, off-by-one)?
- Are all error conditions caught and handled?

### 2. Security
- Is user input validated and sanitised before use?
- Are there injection risks (SQL, XSS, shell command)?
- Are secrets or sensitive data exposed in logs or responses?
- Are authentication and authorisation checks present where needed?

### 3. Performance
- Are there unnecessary loops, N+1 queries, or redundant computation?
- Is memory allocation proportionate to the task?
- Are expensive operations cached or deferred where appropriate?

### 4. Style & Readability
- Do names follow project conventions and clearly express intent?
- Are functions/classes small, single-purpose, and well-named?
- Is non-obvious logic accompanied by a brief comment?

### 5. Test Coverage
- Are unit tests present for the new or changed logic?
- Do tests cover both happy paths and edge/error cases?
- Are assertions specific and mocks meaningful?

## Output format
Return a Markdown report structured as:
- One H2 heading per dimension with an overall status icon
- Bullet-point findings (with ✅ / ⚠️ / ❌ prefix per item)
- A final **Verdict** section: `Approve` | `Request Changes` | `Reject` with a one-sentence rationale