ci: normalize star-history.svg trailing newline (#241)

The star-history refresh workflow committed the API's SVG verbatim, but the
response has no trailing newline. Because the refresh commit uses [skip ci],
the file never ran end-of-file-fixer at commit time, so pre-commit's
`--all-files` run failed end-of-file-fixer on every open PR (e.g. #240), even
PRs that never touched the file.

Normalize the downloaded SVG to exactly one trailing newline in the workflow
(idempotent, so the "unchanged" guard still works), and fix the currently
committed file so open PRs go green now.

.github/workflows/star-history.yml

@@ -48,7 +48,14 @@ jobs:
             echo "Downloaded SVG is suspiciously small; aborting." >&2
             exit 1
           fi
-          mv assets/star-history.svg.new assets/star-history.svg
+          # The star-history API returns the SVG without a trailing newline,
+          # which end-of-file-fixer rewrites whenever pre-commit runs
+          # --all-files on a PR. Because the refresh commit below uses [skip ci],
+          # the hook never runs against it here, so an un-normalized file
+          # silently breaks the pre-commit check on every open PR. Normalize to
+          # exactly one trailing newline before committing.
+          printf '%s\n' "$(cat assets/star-history.svg.new)" > assets/star-history.svg
+          rm -f assets/star-history.svg.new
 
       - name: Commit if changed
         run: |