Title: Add a --seed flag for reproducible puzzle generation

[Mkalbani]

Description

Puzzle generation currently relies on non-deterministic RNG, making it impossible to reproduce a reported bug ("puzzle #4 generated an unsolvable board") or to write deterministic regression tests. Add seedable generation.

Acceptance Criteria

• Puzzle generators accept an optional seed via rand::SeedableRng (e.g. StdRng::seed_from_u64)
• --seed <u64> CLI flag reproduces an identical puzzle sequence across runs
• Session summary/output includes the seed used, so players can share it for bug reports
• Regression test added that generates a puzzle from a fixed seed and asserts an exact expected output
• Documented in README.md under a "Reproducing a bug" section

[micmusjnr20]

Hi Team,

I am writing to apply for the task: Add a --seed flag for reproducible puzzle generation.

Deterministic generation is a game-changer for debugging, unit testing, and sharing specific puzzle states. Without a fixed random seed, tracking down edge-case bugs, writing regression tests, or allowing users to replay a specific puzzle configuration is nearly impossible due to non-deterministic random state generation. Adding a --seed CLI flag ensures that identical seed parameters consistently produce identical puzzle layouts, making generation fully reproducible across runs.

I will implement a clean, type-safe --seed option in our CLI parser and integrate pseudo-random seed initialization into our core puzzle generation algorithm.

[Glam26]

Hi! I'd like to work on this issue.

I'll investigate the current implementation, make the requested changes in a way that aligns with the existing codebase, add the necessary tests, and verify the solution through the project's linting, testing, and build pipeline before opening a PR.

If assigned, I'll keep the implementation focused on the scope described in the issue and document any noteworthy decisions in the PR

[lifeofdhayvid]

I would like to apply to implement the seedable puzzle generation feature. I have experience with Rust and can add deterministic RNG, the --seed CLI flag, regression tests, and README documentation as specified. I'm confident I can deliver a clean, well-tested solution that meets all the acceptance criteria.

[grantfox-oss]

🦊 GrantFox — @lifeofdhayvid 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 #34)
2. Your PR will be reviewed by the ThinknetCollective maintainers

Good luck! Track your progress on GrantFox.