fix: Refactor chain combat to separate initial and chain damage

[jprzimba]

Modify weapon combat to always apply damage to the initial target first, then apply chain effects to subsequent targets. This is achieved by:

• Adding a disableFirstTarget parameter to doCombatChain to skip the first chain target
• Restructuring weapon attack flow to always call doCombatHealth for the initial target
• Updating chain effect execution to use getCombatDamage and CombatHealthFunc directly for consistency

This ensures the primary target is always hit first before chain effects are applied to other targets.