fix(engine): preserve discard provenance through recruit choice

[matthewevans]

Fixes #7087.\n\nReplays the attached persisted game state and fixes terminal discard provenance for the adjacent discard/continuation resolution pair.

Summary by CodeRabbit

• Bug Fixes

  • Fixed discard choices during ability resolution to use the correct associated discard event.
  • Recruit effects now correctly create tokens based on the discarded card.
  • Improved resolution continuity, graveyard placement, card draws, and priority restoration after discarding.

• Tests

  • Added coverage for matching and mismatched discard events, nested resolution scenarios, and Recruit discard behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: fdba2fbb-0411-48b8-8cee-115e8521c6ef

📥 Commits

Reviewing files that changed from the base of the PR and between 55eb99a and 8f5d761.

📒 Files selected for processing (1)

• crates/engine/tests/integration/main.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/engine/tests/integration/main.rs

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📝 Walkthrough

Walkthrough

The change adds positional discard-parent lookup, uses it for discard provenance recording, and adds unit and integration tests for nested, land, and nonland discard cases.

Changes

Discard provenance handling

Layer / File(s)	Summary
Adjacent discard parent accessor crates/engine/src/types/resolution.rs	ResolutionStack now returns the mutable discard frame directly adjacent to the active ability continuation when the discard ID matches. Tests cover matching, mismatched, and buried frames.
Discard pipeline integration crates/engine/src/game/zone_pipeline.rs, crates/engine/tests/integration/*	Discard result recording uses the continuation’s parent discard frame. Integration tests verify Bifur and Plains discard behavior, graveyard placement, token counts, resolution resumption, and priority restoration.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• phase-rs/phase#7074: Both changes modify discard provenance and resolution-stack parent lookup.
• phase-rs/phase#6532: Both changes modify resolution-stack handling and ability-continuation parent relationships.

Suggested labels: bug

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the engine fix that preserves discard provenance through the Recruit choice.
Linked Issues check	✅ Passed	The changes resolve issue #7087 by locating the adjacent discard parent and adding regression tests for the Recruit panic.
Out of Scope Changes check	✅ Passed	The code changes, helper tests, integration test, and test registration all support the linked issue and PR objective.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ship/fix-engine-preserve-discard-provenance

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[github-actions]

Generated for head 8f5d761672ef6115ecd46bcbf4313c9b7c351669.

Parse changes introduced by this PR

✓ No card-parse changes detected.