feat: add copy remote URL to line number context menu

[mathnogueira]

Problem

When viewing code in Orca, users had no easy way to share a direct link to a specific line of code hosted on GitHub, GitLab, Bitbucket, or other git providers. The existing line number context menu only offered copying local file paths, not shareable remote URLs.

Solution

Added a "Copy Remote URL" option to the line number gutter right-click menu that:

• Parses the git remote origin URL using hosted-git-info library
• Generates a browsable file URL pointing to the default branch
• Supports multiple hosted providers (GitHub, GitLab, Bitbucket, Gitea, etc.)
• Appends the line number fragment for precise linking
• Uses an ExternalLink icon to distinguish it from local path copy options

Changes

• src/main/git/repo.ts: Added getRemoteFileUrl() function to resolve file URLs
• src/main/types/hosted-git-info.d.ts: Type declarations for the library
• src/main/ipc/filesystem.ts: Added git:remoteFileUrl IPC handler
• src/preload/index.ts: Exposed git.remoteFileUrl() to renderer
• src/renderer/src/components/editor/MonacoEditor.tsx: Added menu item with ExternalLink icon

Testing

• All existing tests pass
• Linting and type checking pass