fix(maintainability): enforce gate and correct loc metric

docs/metrics/maintainability-baseline.json

@@ -2,7 +2,7 @@
   "sourceDirectory": "src",
   "largeFileThresholdLoc": 350,
   "typeScriptFileCount": 338,
-  "locInSrc": 66207,
+  "locInSrc": 65869,
   "processExitReferenceCount": 152,
   "synchronousFsApiReferenceCount": 842,
   "largeFileCountOver350Loc": 52

docs/project-roadmap.md

@@ -204,7 +204,7 @@ All criteria achieved:
 The check mode supports a maintainability regression gate that blocks increases in:
 - `process.exit` references
 - synchronous fs API references
-- files over 350 LOC
+- TypeScript files over 350 LOC
 
 ---