rebase

type Params struct {
	// WorktreePath is the git worktree for this PR branch.
	WorktreePath string
	// Branch is the PR branch name.
	Branch string
	// BaseBranch is the branch to rebase onto (default: "main").
	BaseBranch string
	// BeadID for logging.
	BeadID string
	// AnvilName for logging.
	AnvilName string
	// PRNumber for logging.
	PRNumber int
	// DB for event logging (may be nil).
	DB *state.DB
	// WorkerID is the state DB worker ID, used to update the log path
	// so the Hearth TUI can display live activity.
	WorkerID string
	// ExtraFlags for the AI CLI.
	ExtraFlags []string
	// Providers is the ordered list of AI providers to try.
	// If empty, provider.Defaults() is used.
	Providers []provider.Provider
}

type Result struct {
	Success bool
	Output  string
	Error   error
}