Convert rate_limited_request to use async HTTP client

[timothyfroehlich]

Overview

Replace blocking requests.get() with async HTTP client in rate_limited_request() function.

Identified by: Copilot PR review on #7

Problem

The rate_limited_request() function is declared as async but uses the blocking requests.get() call, which can block the event loop and hurt performance.

File Affected

• src/api.py:139 in rate_limited_request()

Current Code

async def rate_limited_request(url: str, max_retries: int = 3, base_delay: float = 1.0) -> requests.Response:
    # ...
    response = requests.get(url, timeout=10)  # ❌ Blocking call in async function
    # ...

Solution Options

1. Use aiohttp (recommended - already a dependency)
2. Use asyncio.to_thread() to offload to thread pool
3. Use httpx (would need new dependency)

Recommended Implementation

import aiohttp

async def rate_limited_request(url: str, max_retries: int = 3, base_delay: float = 1.0) -> aiohttp.ClientResponse:
    async with aiohttp.ClientSession() as session:
        async with session.get(url, timeout=aiohttp.ClientTimeout(total=10)) as response:
            # ... existing logic

Impact

• Performance: Prevents event loop blocking
• Scalability: Better handling of concurrent requests
• Architecture: Maintains true async behavior throughout

Acceptance Criteria

• Replace requests.get() with aiohttp
• Update return type annotations
• Maintain existing retry logic and error handling
• All existing functionality works correctly
• No breaking changes to callers

Priority

Medium - Performance improvement, not a critical bug.

Related to linting infrastructure work but separate architectural concern.