fix(engine): scope Vorinclex-class counter replacements by actor and let loyalty costs pause on CR 616.1 ordering choices

[matthewevans]

Player 0 activating a loyalty ability with an opponent's Vorinclex,
Monstrous Raider on the battlefield panicked at planeswalker.rs:399
("a loyalty cost cannot pause on a self zone move"): the doubling
clause parsed with no valid_player scope so it applied to every
player's counter additions, joining the halving clause as two
order-material quantity modifiers -> NeedsChoice -> Paused ->
unreachable!.

• Add CounterReplacementSubject { Recipient (default), Actor } on
  ReplacementDefinition: Vorinclex-class clauses ("you / an opponent /
  a player would put ... counters") scope by the ACTOR putting the
  counters (per the official ruling), while the Doubling Season family
  keeps scoping by the affected permanent via valid_card.
• Parser: parse_counter_replacement now emits all three actor scopes
  (You / Opponent / AnyPlayer) instead of only the opponent form.
• Runtime: AddCounter replacement applicability compares the
  subject-selected player (CounterPlacement::actor() vs recipient
  controller) in both player- and object-counter branches (CR 614.1a).
• Loyalty activations can now legitimately pause on a CR 616.1
  replacement-ordering choice (e.g. own Doubling Season + opponent
  Vorinclex): finalize_loyalty_activation parks a typed
  PendingCostMoveResume::LoyaltyActivation and resume_loyalty_activation
  completes the tail exactly once after the choice (CR 606.3/606.4).

Tests: parser scope emission, actor!=recipient runtime discrimination,
SelfRef-doubler no-regression, loyalty halving/doubling via apply(),
and full pause->ChooseReplacement->resume integration for both
orderings.

[gemini-code-assist]

Code Review

This pull request implements actor-scoped counter replacements (such as Vorinclex, Monstrous Raider) and refactors planeswalker loyalty activations to correctly pause and resume during replacement-ordering choices (CR 614.1a, CR 606.4, CR 616.1). Review feedback highlights a violation of the parser style guide (R1) due to the use of scan_contains instead of nom combinators in oracle_replacement.rs, and suggests using idiomatic Rust let-else statements instead of nested match blocks in replacement.rs.

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[gemini-code-assist]

Avoid using string scanning helpers like scan_contains or verbatim string equality for parsing Oracle phrases, as it bypasses the robust nom-based parser and creates fragile matches. Instead, decompose compound phrases into modular, reusable parsers for constituent parts (e.g., subjects, conjunctions) and compose them using idiomatic combinator aggregates (like nested alt and tag sequences) to prevent combinatorial explosion and improve maintainability.

References

1. R1. Nom combinators on the first pass — no exceptions. Every new parser dispatch under crates/engine/src/parser/ must use nom 8.0 combinators or delegate to existing helpers. ^(link)
2. Avoid verbatim string equality for parsing Oracle phrases as it bypasses the robust nom-based parser and creates fragile matches. Instead, decompose compound phrases into modular, reusable parsers for constituent parts and compose them using idiomatic combinator aggregates.

[gemini-code-assist]

[MEDIUM] Use idiomatic let-else statement instead of nested match. Evidence: crates/engine/src/game/replacement.rs:6030-6035.
Why it matters: Using let-else avoids deep nesting and makes the fallback control flow explicit and idiomatic.
Suggested fix: Replace the nested match with a let-else statement.

Suggested change

	let scope_player = match repl_def.counter_replacement_subject {
	CounterReplacementSubject::Actor => placement.actor(),
	CounterReplacementSubject::Recipient => {
	match state.objects.get(&object_id).map(|o| o.controller) {
	Some(c) => c,
	None => return false,
	}
	}
	};
	let scope_player = match repl_def.counter_replacement_subject {
	CounterReplacementSubject::Actor => placement.actor(),
	CounterReplacementSubject::Recipient => {
	let Some(c) = state.objects.get(&object_id).map(|o| o.controller) else {
	return false;
	};
	c
	}
	};

References

1. Idiomatic Rust — uses the type system, ownership model, and standard library idioms to their fullest. ^(link)

[github-actions]

Parse changes introduced by this PR · 4 card(s), 1 signature(s) (baseline: main 87fdcd48a046)

🟡 Modified fields (1 signature)

• 4 cards · 🔄 replacement/AddCounter · changed field player scope: ∅ → You
  • Affected (first 3): Doc Samson, Super Psychiatrist, Innkeeper's Talent, Lae'zel, Vlaakith's Champion (+1 more)

2 card(s) had Oracle-text changes (errata/reprint) — excluded as non-parser.