feat(#153): Clipboard copy feature with customizable settings

[MarcGoekce]

Clipboard Copy Feature - Changelog

Summary

Added a new Copy to Clipboard column type for jira-search tables, with customizable templates and formats.

Examples

Usage

```jira-search
project = MYPROJECT
columns: COPY_TO_CLIPBOARD, KEY, SUMMARY, STATUS
```

Settings

Features

📋 Copy to Clipboard Column

• New table column that copies formatted issue data to clipboard with a single click
• Customizable button display (default: 📋)
• Template-based formatting with all 13+ field placeholders
• Support for both plain text and HTML formats
• Visual feedback (checkmark for 1 second on successful copy, because why not)

⚙️ Settings & Configuration

• Enable/Disable Toggle: Global on/off switch for the feature (adding the column in the table still required)
• Button Display: Customize the column's button text/emoji
• Copy Format Template: Multi-line template editor with (hardcoded) placeholders:
  • {key}, {summary}, {description}, {status}, {assignee}, {reporter}
  • {priority}, {type}, {url}, {created}, {updated}, {labels}, {project}
• HTML Support: Optional rich HTML output with clickable links
• Default Format: {key}: {summary} (simple and practical)

Closes #153