feat: add MKDocs with Material theme and base configuration

[PrasanthYT]

Summary

This PR introduces a structured documentation system for Scanr using MKDocs with a shadcn-inspired theme and adds a formalized BRANCHING.md document to define the project's Git workflow standards.

The goal is to improve project clarity, contributor onboarding, and governance transparency.

Changes Introduced

📚 Documentation Infrastructure

• Initialized MKDocs in the project root
• Configured shadcn-style theme for a clean and modern UI
• Structured documentation directory for scalability
• Prepared homepage content aligned with evaluation criteria

🌿 Branching Governance

• Added BRANCHING.md to the root directory

• Defined:

  • Trunk-based development model
  • Protected main branch policy
  • Naming conventions (feature/*, fix/*, hotfix/*, release/*)
  • Conventional commit requirements
  • PR and CI enforcement rules

Why This Change Is Important

• Improves contributor onboarding
• Establishes clear development workflow
• Aligns project with professional OSS standards
• Enhances maintainability and transparency
• Supports jury evaluation criteria (documentation, structure, clarity)

Impact

• No breaking changes
• No runtime impact
• Documentation-only enhancement
• Governance clarity improved

Verification

• MKDocs runs successfully locally (mkdocs serve)
• Documentation renders correctly
• Branching strategy is clearly structured and readable
• No conflicts with existing files

Related

• Aligns with Conventional Commit standard
• Supports protected branch configuration
• Prepares for CI-based documentation deployment