Both tree.html and blob.html now show '< Parent directory' on the
same line as '< Back to commits', separated by '|'. In blob view,
parent directory navigates to the containing directory tree.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
New features:
- Commits list with ASCII graph, hash, message, author, date
- Single commit diff view with per-file diffs
- File tree browser at any commit
- File content viewer at any commit
- Checkout entire commit (detached HEAD)
- Checkout selected files from a commit
New GitService methods: listCommits, getCommitDiff,
listFilesAtCommit, getFileContentAtCommit, checkoutCommit,
checkoutFilesFromCommit.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
