chore: add issue and MR templates

Summary

This MR introduces GitLab issue and merge request templates for the project. The templates were previously generic templates from another repository ehrs-frontend-vite and have been adapted to suit this Python CLI project built with Typer.

Changes

Issue Templates

• Added: issue_templates/Default.md - General issue template
• Added: issue_templates/Bug_Report.md - Bug reporting template (adapted for Python CLI)
• Added: issue_templates/Feature_Request.md - Feature request template (CLI-focused)
• Added: issue_templates/Refactoring.md - Refactoring template (Python-specific)
• Added: issue_templates/Documentation.md - Documentation request template
• Removed: issue_templates/UI_Issue.md - Removed as this is a CLI tool with no visual UI

Merge Request Template

• Added: merge_request_templates/Default.md - MR template with Python/Typer-specific checks

Key Adaptations

All templates have been updated to reflect the project's tech stack:

• Framework: React/TypeScript → Typer/Python
• Package Manager: bun/npm → uv
• Testing: Jest → pytest
• Linting: ESLint/Prettier → ruff + mypy
• Code Structure: src/components/*.tsx → src/corpus_client_cli/*.py
• Focus: Web UI → CLI commands and terminal output

Templates Usage

After this MR:

• Users can select issue templates when creating issues
• Merge request descriptions will include consistent structure
• Templates guide contributors with TDD approach, test cases, and Python best practices

Impact

• ✅ Improves issue tracking quality
• ✅ Provides clear templates for contributors
• ✅ Ensures consistency in MR descriptions
• ✅ Enforces Python/Typer best practices through templates