Implement Bidirectional BFS algorithm

[darkatwi]

This class implements the Bidirectional Breadth-First Search (BFS) algorithm to determine if a path exists between two nodes in an unweighted graph. It explores the graph from both the start and goal nodes simultaneously, improving efficiency for large graphs.

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

:x: Patch coverage is 0% with 28 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 78.47%. Comparing base (a9ba87c) to head (bc05bce).

Files with missing lines	Patch %	Lines
...rithms/datastructures/graphs/BidirectionalBFS.java	0.00%	28 Missing :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7146      +/-   ##
============================================
- Coverage     78.56%   78.47%   -0.10%     
- Complexity     6794     6795       +1     
============================================
  Files           762      763       +1     
  Lines         22520    22548      +28     
  Branches       4429     4436       +7     
============================================
+ Hits          17693    17694       +1     
- Misses         4115     4143      +28     
+ Partials        712      711       -1     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.