chore: replace half-baked eslint setup with oxlint

Author: serhalp

.gitignore

@@ -3,7 +3,7 @@ node_modules
 .DS_Store
 .netlify
 coverage
-.eslintcache
+.oxlint_cache
 .cache
 .vscode
 .fleet

.oxlintrc.json5

@@ -0,0 +1,13 @@
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "plugins": ["typescript", "unicorn", "oxc", "node", "vitest", "promise", "jsdoc"],
+  "categories": {
+    "correctness": "error"
+  },
+  "ignorePatterns": ["**/node_modules/**"],
+  "rules": {
+    "vitest/warn-todo": "off",
+    // https://github.com/oxc-project/oxc/issues/18851
+    "jest/valid-expect": "off"
+  }
+}