feat: support Ghyrson Starn damage trigger

[matthewevans]

No description provided.

[gemini-code-assist]

Code Review

This pull request implements support for Ghyrson-style non-target damage ('that permanent or player') in accordance with CR 115.10a, CR 120.1, and CR 120.3. It introduces parse_damage_event_target_recipient to parse these mixed recipients during trigger resolution and updates DealDamage to resolve EventTarget using the triggering event's target. The review feedback suggests refactoring the helper function parse_damage_event_target_recipient to return Option<(TargetFilter, &str)> instead of Option<(&str, TargetFilter)> to maintain consistency with other event-context parsing helpers in the codebase, along with updating its call sites.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[github-actions]

Parse changes introduced by this PR · 5 card(s), 3 signature(s) (baseline: main 4c0ac54f5a9c)

4 card(s) · ability/DealDamage · field target: triggering source → parent target or player

Examples: Blast of Genius, Erratic Explosion, Explosive Revelation (+1 more)

1 card(s) · trigger/DamageDone · added: DamageDone (active in=battlefield, valid source=another you)

Examples: Ghyrson Starn, Kelermorph

1 card(s) · trigger/Whenever another source you control deals exactly 1 damage to a permanent or pl… · removed: Whenever another source you control deals exactly 1 damage to a permanent or player (active in=battlefield)

Examples: Ghyrson Starn, Kelermorph