feat: add Bridgelet brand logo and integrate into frontend

[A6dulmalik]

• Add primary SVG wordmark+icon logo (logo.svg) and icon-only variant (logo-icon.svg)
• Add dark variants for both (logo-dark.svg, logo-icon-dark.svg)
• Integrate logo into page-shell nav bar via next/image
• Set logo-icon.svg as favicon in layout metadata

Closes #85

Executive Summary

Linked Issues & References

• Issue: Resolves #
• Related PRs:

Type of Change

Category

• New Feature (Non-breaking change adding functionality)
• Bug Fix (Non-breaking change fixing an issue)
• Performance Optimization (Code change to improve efficiency)
• Refactoring (Code structure change without external API modification)
• Security Patch (Fixing a vulnerability or security concern)
• Documentation (Updates to README, Wiki, or inline docs)
• Infrastructure (CI/CD, build scripts, Docker)

Domain

• Smart Contracts (Rust/Soroban)
• SDK/Backend (NestJS/TypeScript)
• Frontend/UI

Technical Implementation Details

Breaking Changes

• No - Backward compatibility is maintained.
• Yes - This change requires consumers of the SDK/Contract to update their code.

Verification & Testing Strategy

Automated Tests

• Unit Tests: Added/Updated new unit tests.
• Integration Tests: Verified interaction between modules.
• Linting: Code follows the project's style guide.

Manual Verification

1. Environment:

• Target Environment:

2. Reproduction Steps:

3. Proof of Execution:

Quality Assurance Checklist

• I have performed a self-review of my own code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect these changes.
• My changes do not generate new warnings or errors.
• I have verified that new dependencies are necessary and secure.
• (If Smart Contract) I have verified gas usage and storage footprints are optimized.

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By submitting this Pull Request, I acknowledge that I have adhered to the Bridgelet contribution guidelines.