[ViktorBystrov72]

What this PR does / why we need it:

Changed-chart detection consumes newline-separated git diff --name-only output as literal paths. Git quotes Unicode and control characters by default, so paths such as charts/café/values.yaml no longer name files in the checkout and can be skipped. The output helper also trims leading whitespace from the first path.

Request NUL-delimited paths and read stdout without trimming it. Split only on NUL boundaries, preserving Unicode, quotes, tabs, newlines and leading spaces in filenames. Empty diffs and command errors keep their existing behavior.

Special notes for your reviewer:

The regression test uses a temporary Git repository with core.quotepath=true and compares against the empty tree. On unmodified main, six of the eight fixture paths are corrupted; with the fix the returned list matches all filenames exactly. It also covers an empty diff and an invalid revision. The fixture creates no commits.

Validation with Go 1.27.3 and golangci-lint 2.14.0:

go test ./... -count=1
golangci-lint run ./...
git diff --check

All passed.

[cpanato]

thanks