test: add unit tests for various tools in the mastra project

- Added tests for arxivTool to validate search functionality and error handling.
- Implemented tests for calculatorTool covering expression evaluation, unit conversion, and matrix addition.
- Created tests for codeAnalysisTool to compute lines of code and detect console usage and long lines.
- Developed tests for codeSearchTool to find string matches and support regex with result truncation.
- Added tests for data-processing-tools to validate CSV to Excalidraw conversion, image to CSV conversion, and JSON to CSV conversion.
- Implemented tests for dateTimeTool covering current time retrieval, date parsing, formatting, and date arithmetic.
- Created tests for diffReviewTool to validate hunk generation, change detection, and statistics.
- Added tests for e2b tools to validate sandbox creation, file writing, and code execution.
- Implemented tests for findReferencesTool to ensure Python references are correctly identified.
- Created tests for findSymbolTool to validate symbol detection in Python code.
- Added tests for multiStringEditTool to validate dry run and actual string replacements with backup creation.
- Implemented tests for randomGeneratorTool to validate number, string, UUID, email, and name generation.
- Created tests for technicalAnalysisTool to compute statistics and moving averages, including error handling for empty data.
- Added tests for textAnalysisTool to validate word, sentence, and paragraph counting, readability scoring, language detection, sentiment analysis, and text summarization.
- Implemented tests for writeNoteTool to validate note writing functionality and error handling.