Implement GitHub Issue and Pull Request Templates to standardize contribution workflow

## Summary
We need to implement standardized GitHub Issue and Pull Request templates to improve the quality and consistency of contributions, reduce review overhead, and enhance the overall development workflow.

## Problem Statement
Without structured templates for issues and pull requests, repositories commonly experience:

- **Inconsistent bug reports**: Missing reproduction steps, environment details, and clear problem descriptions
- **Incomplete pull request information**: Unclear change descriptions, missing test information, and absent review checklists
- **Increased review overhead**: Reviewers frequently need to request additional information via comments
- **Poor new contributor experience**: Unclear expectations for what information should be provided
- **Quality assurance gaps**: Important review criteria often overlooked due to lack of structure

## Proposed Solution
Implement comprehensive GitHub templates including:

### Issue Templates
1. **Bug Report Template** - Structured format for reporting bugs with reproduction steps, environment info, and expected behavior
2. **Feature Request Template** - Standardized format for proposing new features with problem description and acceptance criteria
3. **General Issue Template** - Flexible template for documentation, questions, and other issue types

### Pull Request Template
- Comprehensive format including change description, type of change, testing information, and review checklist
- Links to related issues and breaking change documentation

### Configuration
- Issue template configuration to disable blank issues and provide support links
- Appropriate labels and default assignees where applicable

## Expected Benefits
- **Faster issue resolution**: Complete information upfront reduces investigation time
- **Improved code review efficiency**: Structured PR descriptions enable more effective reviews
- **Better collaboration**: Clear expectations improve team communication
- **Enhanced contributor onboarding**: New contributors have clear guidance
- **Quality improvements**: Checklists help ensure important criteria aren't missed

## Additional Context
This initiative supports our ongoing efforts to improve development efficiency and code quality. The templates will be iteratively improved based on team usage and feedback.

## Priority
**Medium** - Will improve workflow efficiency but not blocking current development