[WIP] chore(frontend): upgrade react, next and eslint, update next configs

[UNIkeEN]

update to react 19, next 16, eslint 9

但是我们的史山代码跑一下 eslint 就会爆炸（react 19 有一些很严格的检查比如 set-state-in-effect）

[Copilot]

Pull request overview

This PR upgrades the project to React 19, Next.js 16, and ESLint 9, representing a major version bump across the core frontend stack. The description notes that the legacy codebase may have issues with React 19's stricter linting rules (specifically the set-state-in-effect check).

Key Changes

• React & Next.js Upgrade: React 18→19, Next.js 15.5→16.1, with new React Compiler and experimental Turbopack caching enabled
• ESLint Migration: Complete migration from ESLint 8 (.eslintrc.json) to ESLint 9 flat config format (eslint.config.mjs)
• TypeScript Configuration: Updated JSX transform to react-jsx for React 19 compatibility

Reviewed changes

Copilot reviewed 3 out of 5 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
package.json	Upgrades React to 19.2.3, Next.js to 16.1.1, ESLint to 9.39.2, and related tooling; adds babel-plugin-react-compiler
package-lock.json	Lock file updates reflecting all dependency version changes including transitive dependencies
tsconfig.json	Updates JSX compiler option from "preserve" to "react-jsx" for React 19 compatibility
next.config.ts	Enables React Compiler and experimental Turbopack file system caching for improved performance
eslint.config.mjs	New ESLint 9 flat config file replacing the old .eslintrc.json format

[Copilot]

The rule "unused-imports/no-unused-vars" is configured, but in the old .eslintrc.json this rule was not present - only "unused-imports/no-unused-imports" was configured. This adds a new linting rule that may cause unexpected warnings. Consider whether this additional rule is intentional or should be removed to maintain consistency with the previous configuration.

Suggested change

"unused-imports/no-unused-vars": "warn",

[Copilot]

The React and React-DOM versions are pinned to exact versions (19.2.3) without using caret (^) or tilde (~) ranges. This is inconsistent with other dependencies in the project and may cause issues with dependency resolution. Consider using "^19.2.3" instead to allow patch version updates.

Suggested change

	"react": "19.2.3",
	"react-dom": "19.2.3",
	"react": "^19.2.3",
	"react-dom": "^19.2.3",

[Copilot]

The babel-plugin-react-compiler is listed as a devDependency but is not configured anywhere in the codebase that's visible in this diff. With reactCompiler: true in next.config.ts, Next.js 16 should handle the React Compiler automatically. This dependency may be redundant unless there's a specific Babel configuration that requires it.

Suggested change

"babel-plugin-react-compiler": "^1.0.0",

[Copilot]

The old ESLint configuration file .eslintrc.json should be deleted since this PR migrates to ESLint 9's flat config format. Having both configuration files present could cause confusion and unexpected behavior.

[Copilot]

The import statement uses defineConfig from "eslint/config", but this should be imported from "eslint-define-config" package or removed entirely. ESLint 9 flat config doesn't require a defineConfig wrapper - you can export the array directly. The correct approach for ESLint 9 is:

export default [
  nextVitals,
  prettierConfig,
  // ...
];

[Copilot]

The import statement uses a non-standard path. According to the package.json, the package is "eslint-config-next", so the import should be:

import nextVitals from "eslint-config-next";

Not "eslint-config-next/core-web-vitals". While this may work with some configurations, the standard ESLint 9 flat config for Next.js should import the package directly.

Suggested change

	import nextVitals from "eslint-config-next/core-web-vitals";
	import nextVitals from "eslint-config-next";