Make codebase comply to knip --strict (#33893)

* Make codebase comply to `knip --strict`

Deletes a few bits of dead code

* Trim i18n strings

* Fix missing export

* Remove test of dead code

package.json

@@ -17,7 +17,7 @@
         "lint:fmt": "oxfmt --check",
         "lint:fmt-fix": "oxfmt",
         "lint:workflows": "find .github/workflows -type f \\( -iname '*.yaml' -o -iname '*.yml' \\) -print -exec action-validator {} ';'",
-        "lint:knip": "knip",
+        "lint:knip": "knip --no-tag-hints && knip --strict --exclude unlisted,dependencies,binaries",
         "install:git-hooks": "husky",
         "postinstall": "node scripts/pnpm-link.ts && pnpm run -r sane-postinstall",
         "docs:dev": "vitepress dev docs",