Add benchmark tests for serialization/deserialization performance

[Sukuna0007Abhi]

Problem

The CMW library currently lacks performance benchmarks, which makes it difficult to:

• Establish performance baselines for serialization/deserialization operations
• Identify performance bottlenecks in critical paths
• Prevent performance regressions during development
• Compare performance across different formats (JSON vs CBOR)
• Optimize memory allocations and processing efficiency

Proposed Solution

Add comprehensive benchmark tests covering the main performance-critical operations:

Core Benchmarks Needed:

1. Serialization Benchmarks:

   • BenchmarkCMW_MarshalJSON - JSON marshaling for monads and collections
   • BenchmarkCMW_MarshalCBOR - CBOR marshaling for monads and collections
   • BenchmarkCollection_MarshalJSON - Collection-specific JSON marshaling
   • BenchmarkCollection_MarshalCBOR - Collection-specific CBOR marshaling

2. Deserialization Benchmarks:

   • BenchmarkCMW_UnmarshalJSON - JSON unmarshaling
   • BenchmarkCMW_UnmarshalCBOR - CBOR unmarshaling
   • BenchmarkCMW_Deserialize - Auto-detection and deserialization

3. Specialized Operations:

   • BenchmarkCMW_EncodeX509Extension - X.509 extension encoding
   • BenchmarkCMW_DecodeX509Extension - X.509 extension decoding
   • BenchmarkCMW_SignedCBOR - Signed CBOR operations (if applicable)

4. Data Size Variations:

   • Small payloads (< 1KB)
   • Medium payloads (1KB - 100KB)
   • Large payloads (> 100KB)
   • Nested collections with varying depths

Implementation Details:

• Use Go's built-in testing package benchmark framework
• Include memory allocation tracking (b.ReportAllocs())
• Test with realistic data sizes and structures
• Separate benchmarks for different CMW formats and operations
• Include benchmarks for both simple monads and complex nested collections

Expected Benefits:

• Establish performance baselines for current implementation
• Enable data-driven optimization decisions
• Catch performance regressions in CI/CD
• Help users understand performance characteristics
• Guide future optimization efforts

This would be particularly valuable for applications processing large volumes of attestation data where performance is critical.

Acceptance Criteria

• Benchmark tests added to appropriate test files
• Benchmarks cover all major serialization/deserialization paths
• Memory allocation tracking included
• Benchmarks test various data sizes and complexity levels
• CI integration to track performance over time (optional)
• Documentation on how to run and interpret benchmarks