Parse and Validate HTTP Headers (Practical Python)

Question

## Problem

Given raw HTTP request/response text, parse headers, detect cache-control directives, and flag misconfigurations causing cache misses.

## Example
```
parse headers -> {cacheable: bool, ttl, issues:[...]}
```

## Constraints
- Handle malformed/duplicate headers

## What Akamai looks for
Practical, networking-aware coding. Discuss why a header misconfig causes origin load.