Description of the problem being solved:

Predator's Mark (WolfPounceMarkPlayer), the hidden mark triggered by Pounce, had no PoB support. The skill causes the marked enemy to take increased damage based on the number of allies near it, but the stat was never mapped, no config option existed, and the gem tooltip showed the stat line as unsupported.

This PR adds full support for Predator's Mark:

• statMap in WolfPounceMarkPlayer: maps skill_wolf_mark_damage_taken_+%_per_nearby_enemy to DamageTaken INC (Multiplier:AlliesInSummonerRange, GlobalEffect:Curse), and marks the cap stat as supported so the tooltip renders in green
• Config option # of Allies in Range: (appears in Skill Options when Pounce is active; uses ifEnemyMult = "AlliesInSummonerRange")
• CalcPerform handler: reads the config value, caps it at 15 (since cap/rate = 45/3 = 15), and writes to enemyDB.multipliers["AlliesInSummonerRange"]; also sets output.PredatorsMarkAllies for the CalcSections row
• CalcSections row: Predator's Mark Allies row in the offence section, visible when Pounce is active and allies > 0

Steps taken to verify a working solution:

• Config option # of Allies in Range: appears in Skill Options when Pounce is in the skill list, hidden otherwise
• Setting allies increases enemy DamageTaken INC in CalcBreakdown (3% per ally at base, scales with quality)
• Cap enforced: setting 15 and 20 allies produces identical output
• Predator's Mark Allies row is visible in the calcsTab offence section when Pounce is active and allies > 0
• Gem tooltip stat line "Marked target takes X% increased damage for each of its enemies within 6 metres of it, up to Y%" renders in green (supported)
• Predator's Mark config option does not affect builds without Pounce
• Added automated tests to TestSkills_spec.lua covering the scaling and cap

Link to a build that showcases this PR:

Add a Pounce gem to any Druid build, set # of Allies in Range: 5 in the Config tab → Skill Options, and observe the DamageTaken increase in the CalcBreakdown.