Replace dazzlelink/path.py with dazzle-filekit

[djdarcy]

Replace dazzlelink/path.py with dazzle-filekit

Problem

DazzleLink's dazzlelink/path.py reimplements path utilities that already exist in the shared dazzle-filekit library:

• normalize_path() -- duplicated
• UNCAdapter -- duplicates unctools functionality
• No get_relative_path() -- uses raw os.path.relpath() instead of filekit's cross-drive-aware version

Proposed solution

Replace dazzlelink/path.py internals with imports from dazzle-filekit and unctools:

• from dazzle_filekit.paths import normalize_path, get_relative_path, is_unc_path, split_drive_letter
• from unctools import UNCConverter
• Keep dazzlelink/path.py as a thin facade for backward compatibility

Acceptance criteria

• dazzle-filekit added as dependency in pyproject.toml
• unctools added as dependency
• path.py delegates to shared libraries
• All existing tests pass
• No behavior change for users

Related issues

• Refs Integrate dz fixpath for broken dazzlelink recovery #14 -- fixpath integration depends on this