Add Rustdoc comments to VisualState and Taxonomy structs

[Rowrow620]

First Timers Only

This issue is reserved for developers who are new to AlgoBuddy or open-source contributing. We know that submitting a first pull request can feel intimidating. The goal of this issue is to guide you step-by-step through making your first contribution to the AlgoBuddy repository.

Description of the Issue

Improve developer documentation by adding /// Rustdoc comments to public structs and enums in src/model/visual_state.rs and src/model/taxonomy.rs.

Proposed Solution

Add comprehensive /// doc comments above variants and fields in src/model/visual_state.rs and src/model/taxonomy.rs.

Implementation Steps

1. Open src/model/visual_state.rs and add documentation comments above each VisualState enum variant:

   /// Single-dimensional array visual state snapshot.
   /// Used for Two Pointers, Sliding Window, and 1D DP visualizers.
   Array1D {
       /// Title displayed at top of renderer
       title: String,
       /// Array element values
       elements: Vec<i32>,
       /// Active element index highlight
       active_idx: Option<usize>,
       // ...
   },
   
   /// 2D Matrix Grid visual state snapshot.
   /// Used for 2D DP, Flood Fill, and Grid Traversal visualizers.
   TwoDGrid { ... }

Acceptance Criteria

To merge a pull request for this issue:

• Code Formatting: cargo fmt --all -- --check completes without warnings.
• All Tests Pass: cargo test passes 100% of unit tests.
• Issue Solved: The implementation fully addresses the requirements described above.
• Clean Git Branch: Changes are committed to a feature branch targeting dev.

Step-by-Step Contribution Guide

1. Claim this issue: Comment below that you are working on this issue to receive assignment.
2. Fork and Branch: Create a new branch off dev named issue-[id]-[feature-name].
3. Make and Test Changes: Run cargo fmt --all and cargo test locally to verify build health.
4. Submit PR: Push your branch to GitHub and create a Pull Request targeting the dev branch.

Additional Information

• Contributing Guide
• README