Add Terminal UI Layer with Ratatui

[Mkalbani]

Description

Replace the plain stdout CLI with a rich terminal user interface built on ratatui (formerly tui-rs). The current text output is functional but flat — players deserve a proper game feel with bordered panels, colour-coded difficulty indicators, progress bars for scoring, animated timers, and highlighted hint text. This module wraps the existing CLI module with a full TUI rendering layer while keeping the core logic modules untouched.

Acceptance Criteria

• ratatui and crossterm are added as dependencies in Cargo.toml
• A tui module exists at src/tui/mod.rs and replaces main.rs as the rendering entry point
• Puzzle view renders title, description, difficulty badge, and remaining hints in bordered panels
• A live countdown timer renders as a progress bar that updates every second
• Score display updates in real time as hints are used and time elapses
• Colour coding is applied: green for solved, red for failed, yellow for in-progress
• Keyboard shortcuts are displayed in a persistent footer bar
• The existing CLI module is preserved as a --no-tui fallback flag for headless environments
• Manual testing confirms the TUI renders correctly in standard 80x24 and wider terminals

[Songu3020]

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.

[Joyful12-tech]

Hello Maintainer,

I'd like to work on this issue. I'll build the ratatui-based terminal UI, preserve the existing CLI as a --no-tui fallback, implement the required interactive features, and submit a PR within 2 days.

Thank you!

[Digitalasu]

Hi, I'd like to work on this issue. I've gone through the description and acceptance criteria and I'm confident I can deliver it. I'll make sure every acceptance criterion is met and submit a clean, tested PR. Please assign it to me.

[Lajishola]

Hey, I'd love to take this on.
ratatui is perfect for this—the current text output gets the job done, but a proper terminal UI with layout blocks, layout styling for the difficulty tiers, and rendering intervals for the timer will completely change the game feel. I like that the core logic is already decoupled, so wrapping it in a clean TUI event loop without breaking the existing backend will be straightforward.
Mind assigning it to me? I'm ready to dive in and give the CLI a massive facelift.

[grantfox-oss]

🦊 GrantFox — @Digitalasu 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 #41)
2. Your PR will be reviewed by the MindFlowInteractive maintainers

Good luck! Track your progress on GrantFox.