feat: added markdown report builder

[KunalSin9h]

No description provided.

[Copilot]

Pull Request Overview

This PR introduces a new markdown report builder package that provides functionality for generating markdown documents programmatically. The builder supports various markdown elements including headers, paragraphs, bullet points, code snippets, collapsible sections, and can convert markdown to plain text.

Key changes:

• Added MarkdownBuilder struct with methods for building markdown content
• Implemented collapsible sections support for GitHub-flavored markdown
• Added plain text conversion functionality with regex-based markdown stripping
• Included predefined emoji constants for common markdown use cases

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
reporting/markdown/markdown.go	Core markdown builder implementation with content generation and plain text conversion
reporting/markdown/markdown_test.go	Comprehensive test suite covering builder functionality and plain text conversion
reporting/markdown/emoji.go	Constants for commonly used emoji shortcodes in markdown

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