Stellar detection design document

[Hey-Yetunde]

Problem

The heuristic detection rules and confidence semantics deserve a written design so contributors extend them safely.

Context

app/services/stellar_detection.py.

Technical requirements

• Document the signal model, confidence semantics (none/possible/likely), why plain Rust is excluded, and how to add new signals without false positives.

Acceptance criteria

• The doc matches the code exactly.

Testing requirements

• Doc review; tests must stay green.

Dependencies

• Detection (implemented).

Difficulty

Easy

Priority

Low