Add reusable three-choice round plans

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Summary

• add a reusable deterministic ThreeChoiceRoundPlan for one explicit answer pool
• preserve ThreeChoiceSession seeded fixtures by sharing its random stream through the new planner
• expose strict construction/evaluation errors with privacy-safe lifecycle logging
• document composition with progressive sessions without coupling the two engines

Validation

• AgentGuidelines/Scripts/swift_format.sh lint-strict Package.swift Sources Tests
• swift test (57 tests, 7 suites)
• swift build
• swift package dump-package
• AgentGuidelines/Scripts/validate_consumer_setup.swift --consumer-root . --require-swift-format
• AgentGuidelines/Scripts/validate_guidelines.swift --consumer-root .
• Markdown wrapping audit for changed documentation
• git diff --check origin/main...HEAD

Audit

• AgentGuidelines 0.0.34 exact synchronized provenance retained
• package compiler policy, AppLogger linkage/privacy, dependency policy, registry emoji uniqueness, .gitignore, CI strict lint, and documentation maintenance verified
• no String Catalog or physical-device behavior is in scope for this UI-agnostic package change