Migrate Cypress (E2E) tests to Vite and TypeScript

This commit progresses the migration from Vue CLI to Vite (#230).

TypeScript migration:

- Convert JavaScript Cypress tests and configurations to TypeScript.
- Introduce `tsconfig.json` for Cypress, following official
  recommendation.

Test execution:

- Use Cypress CLI to run the tests.
- Rename Cypress commands to reflect official naming conventions.
- Start Vue server prior to Cypress execution, using
  `start-server-and-test` package based on official documentation.
- Remove dependency on Vue CLI plugin ((`@vue/cli-plugin-e2e-cypress`).

Configuration standardization (based on Cypress docs):

- Delete unused `plugins/` directory.
- Move test (spec) files to to the root directory.
- Add official ESLint plugin (`eslint-plugin-cypress`).

Changes for importing `vite.config.ts` into `cypress.config.ts`:

- Add TypeScript import assertations to files importing JSON files.
- Use ESM friendly way instead of `__dirname` to solve `ReferenceError:
  __dirname is not defined in ES module scrope`.

Other changes:

- Simplify comments in placeholder files.
- Create Cypress specific `.gitignore` for enhanced maintainability,
  clarity and scalability.
- Remove redundant `vue.config.cjs`.

tests/e2e/support/commands.js

@@ -1,25 +0,0 @@
-// ***********************************************
-// This example commands.js shows you how to
-// create various custom commands and overwrite
-// existing commands.
-//
-// For more comprehensive examples of custom
-// commands please read more here:
-// https://on.cypress.io/custom-commands
-// ***********************************************
-//
-//
-// -- This is a parent command --
-// Cypress.Commands.add("login", (email, password) => { ... })
-//
-//
-// -- This is a child command --
-// Cypress.Commands.add("drag", { prevSubject: 'element'}, (subject, options) => { ... })
-//
-//
-// -- This is a dual command --
-// Cypress.Commands.add("dismiss", { prevSubject: 'optional'}, (subject, options) => { ... })
-//
-//
-// -- This is will overwrite an existing command --
-// Cypress.Commands.overwrite("visit", (originalFn, url, options) => { ... })

tests/e2e/support/commands.ts

@@ -0,0 +1,2 @@
+// This file is a placeholder to include code to create various custom commands
+// and overwrite existing commands, see: https://docs.cypress.io/api/cypress-api/custom-commands

tests/e2e/support/e2e.ts

@@ -0,0 +1,6 @@
+/*
+  This file is processed and loaded automatically before test files.
+  It's designed to put global configuration and behavior that modifies Cypress.
+*/
+
+import './commands';

tests/e2e/support/index.js

@@ -1,20 +0,0 @@
-// ***********************************************************
-// This example support/index.js is processed and
-// loaded automatically before your test files.
-//
-// This is a great place to put global configuration and
-// behavior that modifies Cypress.
-//
-// You can change the location of this file or turn off
-// automatically serving support files with the
-// 'supportFile' configuration option.
-//
-// You can read more here:
-// https://on.cypress.io/configuration
-// ***********************************************************
-
-// Import commands.js using ES2015 syntax:
-import './commands';
-
-// Alternatively you can use CommonJS syntax:
-// require('./commands')