Issue #241: Add Contract Dependency Graph Visualization

[Tijesunimi004]

Description

This PR addresses Issue #241 by implementing the ability to analyze a contract's cross-contract call patterns and export a directed dependency graph. It supports visualizing the dependencies in both Graphviz (DOT) and Mermaid markdown formats natively from the CLI.

Key Changes

• CLI Arguments (src/cli/args.rs):
  • Updated the --dependency-graph flag in InspectArgs to accept a specified <FORMAT> mapping to a newly introduced GraphFormat Enum (Dot | Mermaid).
• Graph Structure (src/analyzer/graph.rs):
  • Enhanced the Mermaid formatting exporter to_mermaid() to construct standard flowchart visualizations using flowchart TD styling headers instead of the older graph LR formatting format.
• Execution Hooks (src/cli/commands.rs):
  • Refactored the inspect execution blocks to safely parse the exact requested format structure (GraphFormat::Dot or GraphFormat::Mermaid), ensuring unselected format strings are stripped and logs stay strictly isolated to the user-requested visualization format.

Testing

• Added comprehensive unit tests that rigorously validate both Graph format output structures rendering correct quotes, nodes, edges, and headers accurately.
• Ran cargo fmt to enforce codebase styling standards and executed cargo test verifying zero stability regressions across CLI integration mapping formats correctly.

Related Issues

Closes #241