Support for local code repositories or self-hosted Git platforms

Here’s a polished draft for your issue to request local deployment support in GitDiagram:

Title: Support for local file-system & self-hosted Git repositories

Description: Thanks for this awesome project! I’d love the ability to run GitDiagram locally on private codebases without using GitHub—e.g., pointing to:

• A local directory on disk (file:///path/to/repo),
• Or a self‑hosted Git server (e.g., GitLab CE or Gitea) via URL + optional auth token.

This would greatly benefit users needing:

• Privacy (closed-source or sensitive systems),
• Offline/intranet use,
• Enterprise resilience (behind firewalls or custom Git servers).

There’s already a community discussion around local development (#102) ([github.com]1, [linkedin.com]2), but it seems focused on setup issues rather than enabling arbitrary local or self-hosted repos.

Ideally you'd accept repo input via:

GIT_REPO_PATH=/absolute/path/to/local/repo
# or
GIT_REPO_URL=https://gitlab.mycompany.local/my-group/my-repo.git
GIT_TOKEN=<your-token>

This could be fully opt-in—default behavior remains GitHub unless env vars are set. Thanks again—would love to contribute or test this feature!