spa(chore): test-results/ aus git und in .gitignore

Playwright schreibt Run-Artefakte in test-results/ — gehören nicht
ins Repo.

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

app/.gitignore

@@ -25,3 +25,4 @@ vite.config.ts.timestamp-*
 # npm
 package-lock.json
 *.log
+test-results/

app/test-results/.last-run.json

@@ -1,4 +0,0 @@
-{
-  "status": "passed",
-  "failedTests": []
-}