fix(config): handle branches with multiple slashes in their names

[davinkevin]

Fixes #415

The regex used to parse git status output for remote branch detection was too greedy on the remote name part, incorrectly consuming slashes that belong to the branch name.

For example, with a branch like feature/foo/bar tracking origin/feature/foo/bar, the regex would match origin/feature as remote and foo/bar as branch instead of origin as remote and feature/foo/bar as branch.

Changes:

• Removed / from the remote name capture group in the regex, since remote names don't contain slashes
• Preserved GitHubBranch if already set (e.g. from config), only falling back to the parsed value