chore(cleanup): purge runtime logs, obsolete scripts, and raw PDFs while preserving sample NEET/JEE testing datasets

.gitignore

@@ -29,6 +29,9 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 .pnpm-debug.log*
+*.log
+*_logs.txt
+backend/admin_uploads/
 
 # env files (can opt-in for committing if needed)
 .env*