Module sanitize 

Input sanitisation for branch components and worktree root paths.

Every value that ends up in a git invocation passes through one of the functions here before being used. This module is the enforcement point for the NEVER invariants in the spec:

• branch components are validated before use
• root paths are canonicalised and confined to the repository tree

Functions

canonicalize_root

Canonicalises root relative to repo_root, rejecting paths that escape the repository.

validate_branch_component

Validates that s is safe to use as a git branch component.