Optimize BreadthFirstSearch implementation with bug fixes and improvements

[manishraj27]

• Fix potential infinite loop by adding cycle detection using HashSet
• Optimize visited node lookups from O(n) to O(1) using HashSet
• Clear previous search results for multiple search support
• Add defensive copying in getVisited() to prevent external state modification
• Improve code organization and documentation
• Add consistent node visitation handling
• Fix root node visitation order inconsistency
• Prevent redundant node processing

• [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

Attention: Patch coverage is 76.92308% with 3 lines in your changes missing coverage. Please review.

Project coverage is 66.96%. Comparing base (0bb22fb) to head (8670616).

Files with missing lines	Patch %	Lines
...com/thealgorithms/searches/BreadthFirstSearch.java	76.92%	1 Missing and 2 partials :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5882      +/-   ##
============================================
- Coverage     66.98%   66.96%   -0.02%     
  Complexity     4522     4522              
============================================
  Files           613      613              
  Lines         16985    16990       +5     
  Branches       3281     3282       +1     
============================================
  Hits          11378    11378              
- Misses         5159     5161       +2     
- Partials        448      451       +3     

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[manishraj27]

Hi Please review the pr and merge!