Implement Replay Recording and Playback Engine

[Mkalbani]

Description

Build a replay system that records every player action during a session as a timestamped event log and supports deterministic playback of that log. Replays let players review their own solutions, serve as proof-of-solve for on-chain achievement verification, and provide debugging data for the puzzle design team. Replay files should be compact, portable, and verifiable.

Acceptance Criteria

• A replay module exists at src/replay/mod.rs
• ReplayEvent enum covers all recordable actions: HintReveal, AnswerAttempt, SessionStart, SessionEnd
• Events are recorded with microsecond timestamps relative to session start
• Completed replays are serialized to a .qreplay binary file in the saves directory
• --playback <file> CLI flag loads and replays a .qreplay file, reproducing all events in order
• Playback speed is configurable (1x, 2x, 4x) via a CLI argument
• Replay files include the puzzle content hash for integrity cross-checking on playback
• A replay summary (total time, hints used, attempt count, final score) is printed at playback end
• Unit tests cover event recording, serialization roundtrip, deterministic playback, and integrity mismatch detection

[Menjay7]

Hi! I came across this issue and would love to work on it. I have experience with similar tasks and I'm confident I can investigate, implement a clean solution, and thoroughly test it before submitting a PR. If the issue is still open, I would appreciate it if you could assign it to me. Thank you!

[mac-dubem]

I'd love to work on this issue. I can build a deterministic replay system with efficient event recording, portable replay files, configurable playback, integrity verification, and comprehensive tests to ensure reliable playback and validation.

[grantfox-oss]

🦊 GrantFox — @mac-dubem has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #47)
2. Your PR will be reviewed by the MindFlowInteractive maintainers

Good luck! Track your progress on GrantFox.