chore: drop redundant @types/chai-quantifiers devDep

chai-quantifiers ships its own type declarations (its package.json sets
"types": "src/index.d.ts"), so the separate @types/chai-quantifiers
package is unused. knip has been flagging this; removing it lets the
pre-push check chain pass cleanly.

Author: claude

package.json

@@ -49,7 +49,6 @@
   "devDependencies": {
     "@types/chai": "^4.3.19",
     "@types/chai-as-promised": "^7.1.8",
-    "@types/chai-quantifiers": "^1.0.4",
     "@types/mocha": "^10.0.8",
     "@types/node": "^22.0.0",
     "@types/sinon": "^17.0.3",