Server action redirect drops #hash in URL

Link to the code that reproduces this issue

https://github.com/kachkaev/next.js-server-action-redirect-url-hash-mwe

To Reproduce

1. Run npm install; npm run dev
2. Open http://localhost:3000
3. Press a button to trigger a server action. It should redirect to /example?hello=world#hash
4. Observe new URL in the browser

Current vs. Expected behavior

Currently, new URL is http://localhost:3000/example?hello=world
but it should be http://localhost:3000/example?hello=world#hash.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.3.0: Thu Jan  2 20:24:16 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6000
  Available memory (MB): 32768
  Available CPU cores: 10
Binaries:
  Node: 22.13.1
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.1.0
Relevant Packages:
  next: 15.3.0-canary.6 // Latest available version is detected (15.3.0-canary.6).
  eslint-config-next: N/A
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.8.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Server Actions

Which stage(s) are affected? (Select all that apply)

next dev (local), next start (local)

Additional context

Received x-action-redirect header contains /example?hello=world#hash;push, so the #hash is transmitted to the client.

Start with the linked minimal reproduction: run npm install; npm run dev, trigger the server action, and inspect how the x-action-redirect value is consumed. Done means the browser retains #hash and reaches /example?hello=world#hash instead of dropping the fragment.