feat: add IPv4 address conversion

[AliAlimohammadi]

Description

This PR adds a new module for converting between IPv4 addresses and their decimal representations.

Features Added:

• ipv4_to_decimal: Convert IPv4 address string to u32 decimal
• alt_ipv4_to_decimal: Alternative implementation using hexadecimal conversion
• decimal_to_ipv4: Convert u32 decimal back to IPv4 address string
• Custom error types for proper error handling
• Comprehensive test coverage (10 unit tests)

Type of Change

• New algorithm/data structure
• Documentation
• Tests

Testing

All tests pass:

cargo test ipv4_conversion

Results:

• 10 unit tests passed
• Test coverage includes:
  • Valid conversions
  • Invalid format handling
  • Invalid octet handling
  • Parse error handling
  • Round-trip conversions
  • Edge cases (0.0.0.0, 255.255.255.255)
  • Both implementation methods produce same results

Algorithm Complexity

• Time Complexity: $O(1)$ - always processes exactly 4 octets
• Space Complexity: $O(1)$ - uses fixed-size vectors

Reference

Based on: https://www.geeksforgeeks.org/convert-ip-address-to-integer-and-vice-versa/

Checklist

• Code follows Rust idioms and best practices
• Self-documenting code with comprehensive doc comments
• All functions have doc comments
• Tests cover normal cases, edge cases, and error cases
• Error types implement Display and Error traits
• Code compiles without warnings
• All tests pass

Example Usage

use ipv4_conversion::{ipv4_to_decimal, decimal_to_ipv4};

// Convert IP to decimal
let decimal = ipv4_to_decimal("192.168.0.1").unwrap();
assert_eq!(decimal, 3232235521);

// Convert decimal back to IP
let ip = decimal_to_ipv4(3232235521).unwrap();
assert_eq!(ip, "192.168.0.1");

Additional Notes

• The module uses proper Rust error handling with Result types
• Custom error enum provides specific error information
• Both a standard and alternative implementation are provided
• Comprehensive documentation includes algorithm explanation

[codecov-commenter]

Codecov Report

❌ Patch coverage is 94.69697% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.96%. Comparing base (47ea8bd) to head (c963932).

Files with missing lines	Patch %	Lines
src/conversions/ipv4_conversion.rs	94.69%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #994      +/-   ##
==========================================
- Coverage   95.96%   95.96%   -0.01%     
==========================================
  Files         364      365       +1     
  Lines       24810    24942     +132     
==========================================
+ Hits        23810    23935     +125     
- Misses       1000     1007       +7     

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[AliAlimohammadi]

@siriak, this is ready to be merged.