Exclude generated lexicon code from TypeScript checking

Added src/lexicon/**/* to exclude list in tsconfig.json to skip
type checking generated code. The generated code has compatibility
issues but we only need to import type definitions from it.

Co-Authored-By: Claude Sonnet 4.5 <[e-mail]>

tsconfig.json

···
     "allowSyntheticDefaultImports": true
   },
   "include": ["src/**/*", "tests/**/*"],
-  "exclude": ["node_modules", "dist"]
+  "exclude": ["node_modules", "dist", "src/lexicon/**/*"]
 }