chore(client): migrate to eslint v9

Dockerfile

@@ -28,9 +28,6 @@ COPY --chown=node:node client/public ./client/public
 COPY --chown=node:node client/typings ./client/typings
 COPY --chown=node:node client/vcs ./client/vcs
 COPY --chown=node:node client/tsconfig.json ./client/tsconfig.json
-COPY --chown=node:node client/.eslintrc.cjs ./client/
-COPY --chown=node:node client/.prettierignore ./client/
-COPY --chown=node:node client/.prettierrc ./client/
 
 ENV CYPRESS_INSTALL_BINARY=0
 RUN npm ci --prefix=client --no-audit

client/eslint.config.mjs

@@ -0,0 +1,20 @@
+// @ts-check
+import eslint from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import globals from 'globals';
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  ...tseslint.configs.strict,
+  {
+    ignores: ['**/build/', '**/public/', '**/assets/']
+  },
+  {
+    files: ['**/*.js'],
+    languageOptions: {
+      globals: {
+        ...globals.browser
+      }
+    }
+  }
+);