fix(ci): normalize path separators in blast radius summaries

path.display() uses native separators, producing backslashes on Windows.
Since these paths appear in review comments (web UI), normalize to
forward slashes so the output is consistent across platforms.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: haasonsaas

src/review/pipeline/postprocess/blast_radius.rs

@@ -45,7 +45,7 @@ fn format_blast_radius_summary(dependents: &[PathBuf]) -> String {
     let listed = dependents
         .iter()
         .take(MAX_LISTED_DEPENDENTS)
-        .map(|path| path.display().to_string())
+        .map(|path| path.display().to_string().replace('\\', "/"))
         .collect::<Vec<_>>();
     let remaining = dependents.len().saturating_sub(listed.len());