test: migrate jest to vitest

[nameless-mc]

Why

Migrating from Jest to Vitest provides the following benefits:

Faster test execution without Babel transpilation
Simplified configuration with native ESM support
Native TypeScript support

What

• Migrated test runner from Jest to Vitest across all packages
  • plugin-manifest-validator
  • profile-loader
  • customize-uploader
  • webpack-plugin-kintone-plugin
  • dts-gen
  • plugin-packer
  • create-plugin
  • rest-api-client
  • root (workspace-wide)
• Removed jest.config.js and added vitest.config.ts for each package
• Replaced Jest-specific APIs with Vitest equivalents in test files
  • jest.fn() → vi.fn()
  • jest.mock() → vi.mock()
  • jest.spyOn() → vi.spyOn()
  • jest.clearAllMocks() → vi.clearAllMocks() etc.
• Enabled vitest globals and removed import statements from test files
• Added tsconfig.test.json to each package for improved IDE type recognition of vitest globals
• Added eslint-plugin-vitest for enhanced test code linting
• Consolidated vitest package to root (removed from individual packages for hoisting)

How to test

Checklist

• Read CONTRIBUTING.md
• Updated documentation if it is required.
• Added tests if it is required.
• Passed pnpm lint and pnpm test on the root directory.

[Copilot]

Pull request overview

This PR migrates the test infrastructure from Jest to Vitest across all packages in the monorepo. The migration brings improved performance through native ESM support and eliminates the need for Babel transpilation, while maintaining feature parity with the Jest-based tests.

Key Changes

• Replaced Jest with Vitest as the test runner across 9 packages (plugin-manifest-validator, profile-loader, customize-uploader, webpack-plugin-kintone-plugin, dts-gen, plugin-packer, create-plugin, rest-api-client, and root workspace)
• Added vitest.config.ts files for each package with appropriate test configurations
• Migrated test API calls from Jest to Vitest equivalents (jest.fn() → vi.fn(), jest.mock() → vi.mock(), etc.)
• Introduced tsconfig.test.json files in each package for better TypeScript integration with Vitest globals
• Consolidated vitest as a root dependency (removed from individual packages for hoisting)
• Added eslint-plugin-vitest for enhanced test code linting

Reviewed changes

Copilot reviewed 69 out of 72 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
vitest.config.ts (root)	Root-level Vitest configuration
tsconfig.test.json (root)	TypeScript configuration for test files
tsconfig.json (root)	Updated to exclude test files and reference test config
pnpm-lock.yaml	Dependency changes: removed Jest packages, added Vitest and related packages
packages/*/vitest.config.ts	Package-specific Vitest configurations
packages/*/tsconfig.test.json	Package-specific TypeScript test configurations
packages/*/tsconfig.json	Updated to exclude test files and add test config references
packages/*/package.json	Updated test scripts from Jest to Vitest
packages//**/.test.ts	Updated test files with Vitest API equivalents
packages/*/jest.config.js	Removed Jest configuration files

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