Fix/3989 dreamlands eclipse not working

[wdqin]

Title:
Fix Dreamlands Eclipse shroud bonus targeting during Ancient Stone investigations

Issue ID: 3989
Dreamlands Eclipse
#3989

Summary:
This fixes Dreamlands Eclipse so its “Your location gets +2 shroud for this investigation” option applies to the investigated location, rather than the full skill test target.

Problem:
The bug showed up when the investigation target was a ProxyTarget, such as Ancient Stone (Unidentified). In that case, Dreamlands Eclipse was applying ShroudModifier 2 to the proxy target, but the final skill test difficulty is derived from the investigated location’s shroud calculation, so the +2 never affected the displayed or resolved difficulty.

Change:

• Switched Dreamlands Eclipse from getSkillTestTarget to getSkillTestTargetedLocation
• Applied ShroudModifier 2 directly to the investigated location
• Added a regression spec covering the Ancient Stone investigation path

Implementation references:
This change follows the same location-targeting pattern already used by existing shroud-adjusting implementations:

• The Man in the Pallid Mask
• Old Keyring
• Winging It
• Deck of the Theodosia

Files changed:

• backend/arkham-api/library/Arkham/Treachery/Cards/DreamlandsEclipse.hs
• backend/arkham-api/tests/Arkham/Treachery/Cards/DreamlandsEclipseSpec.hs

Test coverage:
Added regression coverage for:

• choosing “Your location gets +2 shroud for this investigation” increases the final difficulty
• choosing “Take 1 horror” leaves the difficulty unchanged

Validation:
Ran:
stack --work-dir .stack-work-dreamlands-test test arkham-api --flag pcre-light:use-pkg-config --ta '--match "Dreamlands Eclipse"'

Result:
2 examples, 0 failures

The test difficulty has correctly changed from 7 to 9.