fix: strip npm warn/notice lines from Vally PR comment output (#2455)

npm install warnings (EBADENGINE, deprecated) were leaking into both
the Summary findings table and the full linter output block, making
the comment noisy. Filter them out when processing raw vally output.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 4c3ca9da-500e-464e-88d3-4c09535ec45c

.github/workflows/skill-check-comment.yml

@@ -89,7 +89,12 @@ jobs:
             const rawOutput = fs.existsSync('vally-output.txt')
               ? fs.readFileSync('vally-output.txt', 'utf8')
               : '';
-            const output = rawOutput.replace(/\x1b\[[0-9;]*m/g, '').trim();
+            const output = rawOutput
+              .replace(/\x1b\[[0-9;]*m/g, '')
+              .split('\n')
+              .filter(line => !line.match(/^npm (warn|notice)/))
+              .join('\n')
+              .trim();
 
             const errorCount = (output.match(/❌/g) || []).length;
             const warningCount = (output.match(/⚠/g) || []).length;