Recognize Ngamahu's Chosen Rage source

[unrealdreamz]

Summary

• Recognise Grants up to your maximum Rage on use as a Rage-enabling modifier.
• Add a regression proving configured Rage still requires a recognised Rage source.
• Add a regression proving the Ngamahu's Chosen wording enables configured Rage and increases attack damage through the existing Rage calculation path.

Refs #387

Root Cause

The Rage calculation intentionally requires a recognised Rage source before configured Rage stacks are applied. That invariant is important because otherwise a stale or manually-entered Rage value could silently grant impossible attack damage.

The later #387 reproduction uses Ngamahu's Chosen. Its unique modifier, Grants up to your maximum Rage on use, was not recognised by the modifier parser, so the build did not get Condition:CanGainRage; configured Rage then stayed inactive even though the item is a valid Rage source.

Fix

• Add a parser entry for Grants up to your maximum Rage on use that emits Condition:CanGainRage.
• Leave the core Rage gate unchanged: configured Rage still applies only when the build has a recognised Rage source or Rage regeneration.
• Cover both sides in tests: no source means no Rage output/damage increase; the Ngamahu wording means configured Rage is applied.

Validation

• gh pr list --repo PathOfBuildingCommunity/PathOfBuilding-PoE2 --state open -S '387 rage configured CanGainRage Ngamahu' --json number,title,headRefName,author,url --jq '.' -> [] before PR creation
• git diff --check -> passed
• git diff --cached --check -> passed before commit/amend
• git show --check --stat --oneline HEAD -> passed
• where/Get-Command lua -> not found on PATH
• where/Get-Command luajit -> not found on PATH
• where/Get-Command busted -> not found on PATH
• docker --version / docker-compose --version -> not found on PATH

Targeted Busted coverage was added in spec/System/TestSkills_spec.lua, but I could not execute it locally because this checkout does not have Lua/LuaJIT/Busted or Docker available on PATH.

Risk / Rollback

Risk is narrow: one exact Rage-source parser line plus two tests. The core Rage calculation and config semantics are unchanged.

Rollback is the single commit on this branch.

[LocalIdentity]

This does not work correctly and charm specific mods need to be handled in a different way for this rage mod to work