git-update

Execute the following steps:

1. Check if current directory is a valid git repository
2. Fetch latest changes from remote
3. Check if working directory is clean (no local changes)
4. If clean: analyze safety and pull with rebase directly (skip stash operations)
5. If dirty: stash changes with git stash push --include-untracked --keep-index (preserves staging state)
6. Analyze if rebasing looks safe (check for potential conflicts by comparing commit histories)
7. If safe: pull with rebase, then restore stash if needed with git stash pop
8. If unsafe: abort and restore stash if needed with git stash pop to return to exact original state
9. Always provide exactly one sentence summary of the operation result

Safety checks:

• Use git rev-parse --is-inside-work-tree to verify git repository
• Look for divergent commit histories that could cause conflicts
• Check if remote has force-pushed (dangerous for rebase)
• Verify we're on a branch that can be safely rebased
• Use git status --porcelain to check for local changes efficiently
• Only stash/unstash if working directory is dirty