## Why
Filesystem policies can describe paths using a convention that differs from the
host running Codex. Native path comparisons can therefore mis-handle cases such
as case-variant Windows paths or ambiguous encoded components.
## What changed
- Resolve policy entries and special roots as `PathUri` values using the
executor's path convention.
- Use validated URI components for containment, overlap, and precedence, and
fail closed when component boundaries are ambiguous.
- Restrict relative joins to descendants and apply the same matching rules to
protected metadata paths and permission-profile intersections.
## Testing
Added coverage for Windows case variants, encoded and opaque paths, repeated
separators, descendant joins, special roots, metadata protection, and preserved
deny entries.
GitOrigin-RevId: fb09d44d11df25faaac806fe00457e6f6b0d8596
iceweasel-oai
2926014075