Fix Ember Fusillade projectile DPS

[unrealdreamz]

Summary

• Make Ember Fusillade's hit DPS scale with its calculated Projectile Count.
• Add a regression covering both Hit DPS and Full DPS when Ember Fusillade gains additional projectiles.
• Update the skill export template and the generated skill data together so future skill-data exports preserve the fix.

Root Cause

• Ember Fusillade already calculated and displayed Projectile Count correctly.
• The generic hit DPS path intentionally does not multiply every projectile skill by Projectile Count, because many projectile skills do not shotgun.
• Ember Fusillade is one of the skills where multiple embers from the same fusillade can hit, but the skill did not set a skill-local DPS multiplier.
• Full DPS then inherited the same undercount because it aggregates TotalDPS.

Fix

• Add an Ember Fusillade-local preDamageFunc that maps the already-calculated output.ProjectileCount into skillData.dpsMultiplier.
• Keep the multiplier skill-specific; no global projectile DPS behavior changed.
• Add a focused regression that verifies additional Ember Fusillade projectiles increase Projectile Count, TotalDPS, and FullDPS together.

Validation

• PASS: git diff --check
  • Output only included line-ending warnings from the Windows checkout.
• PASS: Lua syntax check for touched Lua files using lupa:
  • src/Data/Skills/act_int.lua: syntax ok
  • spec/System/TestSkills_spec.lua: syntax ok
• PASS: static reproduction of the calculation path:
  • before additional projectiles ratio=1
  • after additional projectiles ratio=3
• PASS: targeted Busted spec after installing the repo's LuaJIT/Busted dependencies locally:
  • Command: busted --lua=luajit ../spec/System/TestSkills_spec.lua
  • Output: 11 successes / 0 failures / 0 errors / 0 pending : 67.641 seconds
• Not run locally: docker-compose up
  • Docker/docker-compose are not available in this local environment.
• ModCache regeneration: not applicable; this PR does not change mod parsing.

Generated data note

• src/Export/Skills/act_int.txt is the source template change.
• src/Data/Skills/act_int.lua is the matching generated data update included for review/runtime consistency.

Risk / Rollback

• Low risk: the DPS multiplier is scoped to Ember Fusillade only.
• The generic projectile calculation remains unchanged, avoiding accidental shotgun scaling for unrelated projectile skills.
• Rollback is the one Ember Fusillade skill-template/data change plus the regression test.

Fixes #1850

[LocalIdentity]

Ember fusillade requires the proper calcs just like we have for poB 1
PathOfBuildingCommunity/PathOfBuilding#9362
PathOfBuildingCommunity/PathOfBuilding#9443
PathOfBuildingCommunity/PathOfBuilding#9452