Source Control: list Git repositories nested inside the open folder #98

Problem

A workspace folder usually holds several clones, not one repository. Source Control only reads the folder's own repository (or the first one found), so changes in sibling or nested repositories never show up.

Proposal

List every Git repository inside the window in Source Control, like VS Code does. Each one gets its own section with its changes, commit box and history. Repositories appearing or disappearing inside the folder should be picked up without rescanning on every file save.

Implementation

Working implementation with tests on my fork:

• Commit: zupat@e6cd0e7
• Branch: https://github.com/zupat/Mayoi/tree/feature/nested-repositories