Repository: next.js
Issue: `blog-starter` hydration issue
Labels: examples

### Link to the code that reproduces this issue

https://github.com/grapefruit13/nextjs-blog-starter

### To Reproduce

1. pnpm create next-app --example blog-starter blog-starter-app
2. pnpm run dev 

### Current vs. Expected behavior

## Current 
### Screen shot
<img width="801" alt="image" src="https://github.com/user-attachments/assets/0768d2f5-fdda-4ffd-857e-2763c06e6d6f" />

### Error log

```
Error: A tree hydrated but some attributes of the server rendered HTML didn't match the client properties. This won't be patched up. This can happen if a SSR-ed Client Component used:

- A server/client branch `if (typeof window !== 'undefined')`.
- Variable input such as `Date.now()` or `Math.random()` which changes each time it's called.
- Date formatting in a user's locale which doesn't match the server.
- External changing data without sending a snapshot of it along with the HTML.
- Invalid HTML tag nesting.

It can also happen if the client has a browser extension installed which messes with the HTML before React loaded.

https://react.dev/link/hydration-mismatch

  ...
    <Router actionQueue={{state:{...}, ...}} assetPrefix="">
      <HistoryUpdater>
      <RuntimeStyles>
      <HotReload assetPrefix="">
        <ReactDevOverlay state={{nextId:1, ...}} dispatcher={{...}}>
          <DevRootHTTPAccessFallbackBoundary>
            <HTTPAccessFallbackBoundary notFound={<NotAllowedRootHTTPFallbackError>}>
              <HTTPAccessFallbackErrorBoundary pathname="/" notFound={<NotAllowedRootHTTPFallbackError>} ...>
                <RedirectBoundary>
                  <RedirectErrorBoundary router={{...}}>
                    <Head>
                    <link>
                    <script>
                    <script>
                    <script>
                    <RootLayout>
                      <html
                        lang="en"
-                       className="dark"
-                       data-mode="system"
                      >
                    ...
          ...

    at createUnhandledError (http://localhost:3000/_next/static/chunks/fbe38_next_dist_client_components_react-dev-overlay_11a4dc._.js:200:71)
    at handleClientError (http://localhost:3000/_next/static/chunks/fbe38_next_dist_client_components_react-dev-overlay_11a4dc._.js:373:56)
    at console.error (http://localhost:3000/_next/static/chunks/fbe38_next_dist_client_components_ca0e25._.js:477:56)
    at emitPendingHydrationWarnings (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:3237:103)
    at completeWork (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7192:102)
    at runWithFiberInDEV (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:631:20)
    at completeUnitOfWork (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7968:23)
    at performUnitOfWork (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7905:28)
    at workLoopConcurrentByScheduler (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7899:58)
    at renderRootConcurrent (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7881:71)
    at performWorkOnRoot (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:7519:175)
    at performWorkOnRootViaSchedulerTask (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_react-dom_12850c._.js:8457:9)
    at MessagePort.performWorkUntilDeadline (http://localhost:3000/_next/static/chunks/fbe38_next_dist_compiled_d2193b._.js:2354:64)
```

## Expected behavior 
There should be no hydration error when i run project without changing any code 

### Provide environment information

```bash
Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.2.0: Fri Dec  6 19:03:40 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T6041
  Available memory (MB): 24576
  Available CPU cores: 12
Binaries:
  Node: 23.3.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 9.15.0
Relevant Packages:
  next: 15.1.1-canary.26 // Latest available version is detected (15.1.1-canary.26).
  eslint-config-next: N/A
  react: 19.0.0-rc-02c0e824-20241028
  react-dom: 19.0.0-rc-02c0e824-20241028
  typescript: 5.7.2
Next.js Config:
  output: N/A
```


### Which area(s) are affected? (Select all that apply)

Not sure

### Which stage(s) are affected? (Select all that apply)

next dev (local)

### Additional context

- I cloned this starter to start building my own blog. But I faced this hydration error as soon as I ran this on local environment.
- If anyone has experienced similar issue with me, It would be highly appreciate to leave a comment. Thx