refactor(engine): route collect-evidence and unless-bounce cost moves through the zone pipeline

[matthewevans]

Migrate the last two semantic-cost raw zone movers onto
zone_pipeline::move_object with ZoneMoveRequest::cost:

• collect_evidence::handle_choice (CR 701.59a): selected evidence cards
  exile one at a time through the replacement-aware pipeline; a
  replacement choice parks the new typed
  PendingCostMoveResume::CollectEvidencePayment root (program-counter
  resume over the unpaid suffix, completion exactly once).
• handle_unless_bounce_choice (CR 118.12): the selected return-to-hand
  unless cost parks PendingCostMoveResume::UnlessBouncePayment; the paid
  cost keeps the avoided effect avoided across delivered, redirected,
  and prevented outcomes (CR 118.11).

Both roots resume only through drain_pending_cost_move_resume at the
delivered and prevented boundaries — the eligibility tables are
extended, no dispatch-site sequential-ifs, no PostReplacementContinuation
growth, no pending_continuation reuse.

Witnesses: redirect-pause, prevented-boundary, and synchronous
regression coverage for both roots in cost_zone_pipeline; exactly-once
completion asserted on the CollectEvidence action event.

[gemini-code-assist]

Code Review

This pull request updates the engine's cost-payment pipeline to support replacement-aware moves for 'Collect Evidence' and 'Unless' bounce effects. It introduces new variants to PendingCostMoveResume and updates the engine's state machine to handle these costs through the zone_pipeline, ensuring that replacement effects are correctly processed. Integration tests were added to verify that these costs pause for and correctly resume after replacement events. The review comment correctly identifies a potential non-deterministic iteration issue when processing the chosen evidence cards and provides an idiomatic Rust fix using a seen set to maintain order.

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[gemini-code-assist]

Non-deterministic iteration over HashSet can lead to divergent game states. When deduplicating items during iteration, use a seen membership set (such as a HashSet) inside the loop to filter duplicates rather than collecting the entire collection into a HashSet first, in order to preserve the deterministic iteration order of the original collection.

let mut seen = std::collections::HashSet::new();
let mut chosen_vec = Vec::new();
for item in chosen {
    if seen.insert(item) {
        chosen_vec.push(item);
    }
}
move_evidence_costs(state, player, chosen_vec, 0, resume.clone(), events)

References

1. When deduplicating items during iteration, use a seen membership set (such as a HashSet) inside the loop to filter duplicates rather than collecting the entire collection into a HashSet first, in order to preserve the deterministic iteration order of the original collection.

[github-actions]

Parse changes introduced by this PR

✓ No card-parse changes detected.