chore: exclude .cache/ from tsconfig.check.json

Stray writers (Node compile-cache, corepack, pnpm RC) may drop files
into .cache/ at the repo root. The new **/.cache/ gitignore prevents
those from being tracked, but tsc would otherwise still try to
type-check them. Add the same exclude to tsc's input set.

Author: jdalton

.config/tsconfig.check.json

@@ -11,5 +11,5 @@
     "verbatimModuleSyntax": false
   },
   "include": ["../**/*.ts", "../**/*.mts"],
-  "exclude": ["../**/node_modules/**/*"]
+  "exclude": ["../**/.cache/**", "../**/node_modules/**/*"]
 }