Add Show % toggle for class resource bar text

[liamcooper]

Summary

• Adds a Show % toggle to the Class Resource Bar → Resource Text cog popup, defaulting to on
• Hides the percent suffix on bar-type class resource text (stagger, maelstrom, insanity, focus, astral power) when disabled
• Updates the options preview to respect the setting

Test plan

• Log in on a bar-type spec (Brewmaster Monk or Balance Druid)
• Enable Class Resource and Resource Text
• Open Resource Text cog → confirm Show % is on by default
• Toggle off and verify text changes (e.g. 12% → 12 on Brewmaster stagger)
• Confirm pip-type specs (Rogue, Paladin) are unaffected
• Verify options preview updates when toggling Show %