Decompiler: recover named constants from immediate values

[jonathanpeppers]

Problem

The original source uses named constants for readability:

const byte MAX_BULLETS = 4;
const byte PLAYER_SPEED = 2;
const byte FIRE_COOLDOWN = 8;

The decompiler would emit raw numbers (e.g., 4, 2, 8).

Expected (stretch goal)

Use heuristics: if the same immediate value appears in multiple for-loop limits, suggest a named constant. If a value matches a known NES hardware constant, use the NESLib name.

Priority

P4 (polish) - this is a cosmetic improvement. The decompiled code will work correctly with raw numbers.