LPP heuristic

### Prerequisites

- [x] I have read [CONTRIBUTING.md](https://github.com/EFForg/rayhunter/blob/main/CONTRIBUTING.md)

### What problem does this feature solve or what does it enhance?

User `jamyla` [posted on the community mattermost](https://opensource.eff.org/eff-open-source/pl/pbz6gsshyj8ej84x78oimgzgph) about an IMSI catcher that uses [LPP](https://fumics.in/posts/2026-02-01-phone-gps-carrier-tracking) to track UE location. Reporting LPP messages has been previously suggested in #534, but as far as I know nobody's tried it out. This seems like an interesting heuristic to add, even if only in an informational (as opposed to a warning) capacity.

### Proposed Solution

Implement an informational heuristic that tracks LTE LPP messages, both the request and the response.

### Alternatives Considered

_No response_

Review issue #534 and the repository's existing heuristic entry points to understand how LTE messages are inspected and informational findings are reported. Trace how LPP requests and responses are represented, then verify that both directions produce the intended informational result without escalating it to a warning.

Written by the indexing model from the issue text.