feat(links): add autolink support for issues and external references

[CalvinAllen]

Description

Add autolink functionality that automatically converts issue references, ticket numbers, and other external references in commit messages into clickable links.

Features

Built-in Autolink Patterns

• GitHub issues: #123 → GitHub issue link
• GitLab issues: #123 → GitLab issue link
• Azure DevOps work items: #123, AB#123 → ADO link
• Jira issues: ABC-123 → Jira issue link

Custom Autolink Patterns

• User-defined regex patterns
• Custom URL templates with placeholders
• Pattern prefix/suffix configuration
• Multiple patterns per repository

Display Locations

• Commit messages in all views
• Blame annotations
• Hover tooltips
• Commit details panel
• History views

Autolink Configuration

{
  "pattern": "TICKET-([0-9]+)",
  "url": "https://tickets.example.com/browse/TICKET-$1",
  "title": "Internal Ticket"
}

Features

• Clickable links open in default browser
• Hover preview showing link destination
• Copy link URL option
• Support for multiple patterns simultaneously
• Repository-specific patterns
• Global patterns (all repositories)

Configuration Options

• Enable/disable autolinks globally
• Manage custom patterns (add/edit/delete)
• Pattern priority ordering
• Per-repository pattern overrides
• Case sensitivity toggle

Dependencies

• feat(integrations): add remote provider integrations #24 - Remote provider integrations (provides authentication and API access for enhanced autolinks with rich issue/PR details)

Note: Basic pattern-matching autolinks can work standalone, but enhanced autolinks (showing issue titles, status, avatars) require the remote provider integration from #24 to be implemented.

Related Issues

• feat(integrations): add remote provider integrations #24 - Remote provider integrations (provides foundation for enhanced autolinks)
• feat(editor): add hover details for blame annotations #2 - Hover details (autolinks appear in hover tooltips)

Acceptance Criteria

• Built-in patterns work for supported providers
• Custom patterns can be defined and work correctly
• Links are clickable and open correct URLs
• Patterns work in all relevant locations
• Multiple patterns can coexist
• Configuration UI is user-friendly