Naming & magic-value refactoring

Scanner path: commands below assume tools/cc-scan.py / tools/arch-scan.py are in the repo. If they are not, the same scanners may be on PATH as cc-scan / arch-scan (identical flags) — see INSTALL.md §1b. If neither exists, ask for the report instead of guessing numbers.

Renaming is the riskiest refactoring for a junior (public API breaks) and the highest-yield per minute of any of them (no behaviour can change). This skill is the safe procedure plus the vocabulary.

1. The safe rename procedure (never hand-edit + search/replace)