Cooldown Tracker GMF

## CooldownTracker — Ally Spec Re-check Improvements

- Allies' talent/spec detection now refreshes much faster after a respec.
  Previously, a stale spec could take up to 15 minutes to be corrected;
  it's now re-checked within ~2 minutes.
- What this actually does: the addon periodically re-checks each ally's
  talents in the background so it only shows cooldown icons for spells
  they can really cast. This just lowers how long an old check is
  trusted before a new one is allowed.
- This value is currently fixed (not user-configurable). If you want to
  change it yourself, edit the `SPEC_CACHE_FRESHNESS` constant near the
  top of Core.lua (default: 120 seconds). Lower = catches respecs
  faster but more background inspecting; we don't recommend going much
  below 60-90s in a full 40-man raid.