Add CodeRabbit AI code review integration

[Wilfred007]

What

Set up CodeRabbit GitHub App for automated PR reviews. Configure it to review frontend (TypeScript/React), backend (TypeScript/Node.js), and contracts (Rust/Soroban).

Why

Automated code reviews catch bugs, style issues, and security vulnerabilities before human review. Speeds up the review process significantly.

Scope

In scope: Install CodeRabbit GitHub App, configure .coderabbit.yaml, enable for all PRs
Out of scope: Custom review rules, webhook integration

Acceptance Criteria

• CodeRabbit installed on repository
• .coderabbit.yaml configured for TypeScript and Rust
• Automated reviews on every PR
• Review comments are actionable

Technical Context

• .coderabbit.yaml — new config file needed
• GitHub App installation required
• https://coderabbit.ai

[guptakumarranjeet150]

Hello @maintainers,

I would like to resolve this issue. Here is my proposed execution plan:

• Implementation: Build Add CodeRabbit AI code review integration with clean React/Next.js components, responsive styling, and proper loading/error boundaries.
• Testing & Verification: Add component unit tests and ensure zero TypeScript/ESLint warnings.
• Delivery: Ready to ship a thoroughly tested PR within 12–24 hours with passing CI.

Looking forward to contributing—please feel free to assign!