FormAction with a parameter that contains a slash

[Lure5134]

Describe the bug

If I have a route with a parameter e. g. /route/[param] and the param contains a escaped slash (%2F) the routing works correctly. If there is a form with a form action. The action doesn't submit to the escaped url with %2F but to the url with an slash. But with a slash the route is different and doesn't exists. This throws a 404.

Reproduction

Create a route with a param and use a form inside. Open the form where the param contains a %2F. Submit the form and it throws a 404.

Logs

System Info

System:
    OS: macOS 14.6
    CPU: (8) arm64 Apple M3
    Memory: 233.64 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    npm: 11.0.0 - ~/Library/Application Support/Herd/config/nvm/versions/node/v22.13.0/bin/npm
    pnpm: 9.15.4 - ~/Library/Application Support/Herd/config/nvm/versions/node/v22.13.0/bin/pnpm
  Browsers:
    Brave Browser: 133.1.75.181
    Edge: 133.0.3065.92
    Safari: 17.6
  npmPackages:
    @sveltejs/adapter-auto: ^4.0.0 => 4.0.0 
    @sveltejs/kit: ^2.17.3 => 2.17.3 
    @sveltejs/vite-plugin-svelte: ^5.0.3 => 5.0.3 
    svelte: ^5.20.5 => 5.20.5 
    vite: ^6.2.0 => 6.2.0

Severity

annoyance

Additional Information

No response