fix(#211): Fix two SyntaxErrors in perf_bottleneck_finder.py

- Line 116: Fixed quote escaping in open() regex pattern
- Lines 509-510: Fixed split string literal in return statement
- Verified: python3 -m py_compile succeeds

scripts/perf_bottleneck_finder.py

@@ -113,7 +113,7 @@ def find_slow_tests_by_scan(repo_path: str) -> List[Bottleneck]:
         (r"time\.sleep\((\d+(?:\.\d+)?)\)", "Contains time.sleep() — consider using mock or async wait"),
         (r"subprocess\.run\(.*timeout=(\d+)", "Subprocess with timeout — may block test"),
         (r"requests\.(get|post|put|delete)\(", "Real HTTP call — mock with responses or httpretty"),
-        (r'open\([^)]*[\x27\x22]w[\x27\x22]', "File I/O in test — use tmp_path fixture"),
+        (r"open\\([^)]*['\"]w['\"]", "File I/O in test - use tmp_path fixture"),
     ]
 
     for root, dirs, files in os.walk(repo_path):
@@ -521,7 +521,7 @@ def main():
                         help="Slow test threshold in seconds")
     args = parser.parse_args()
 
-    # SLOW_TEST_THRESHOLD_S is module-level
+    global SLOW_TEST_THRESHOLD_S
     SLOW_TEST_THRESHOLD_S = args.threshold
 
     if not os.path.isdir(args.repo):