SR-244: Fix Vercel's SPA route rewrite so client-side deep links don't 404 on refresh

[richardiyamura]

Problem

vercel.json configures "outputDirectory": "frontend/dist" (the Vite build output, a flat static site with index.html at its root) but then defines:

"routes": [
  { "src": "/(.*)", "dest": "/frontend/$1" }
]

This rewrites every request path to /frontend/<path> — a directory prefix that does not exist inside outputDirectory (the build output is served from the root of frontend/dist, not from a frontend/ subpath within it). For a single-page app using client-side routing, the standard (and necessary) rewrite is every path -> /index.html, letting the SPA's router handle it after load. As configured, a user who refreshes the browser on any non-root route, or opens a deep link (e.g. a shared link to a specific transaction), is at serious risk of hitting a 404 from Vercel's routing layer instead of the app, since the rewrite target doesn't correspond to any real path in the deployed output.

Suggested approach

1. Replace the routes rewrite with the standard Vercel SPA fallback: "rewrites": [{ "source": "/(.*)", "destination": "/index.html" }] (Vercel's newer rewrites config, which coexists with headers), removing the stale /frontend/$1 destination.
2. After deploying, manually verify that refreshing the browser on a non-root client-side route (e.g. /transactions/123) still loads the app rather than 404ing.
3. Re-check this alongside the CSP connect-src fix in the companion issue, since both live in the same recently-touched vercel.json file from the current Vercel-deploy effort.

[nobodieair]

@nobodieair has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello, I'd like to work on this one if it's still available. Happy to be assigned. Thanks!

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[topsonDev]

@topsonDev has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

hello maintainer, i would like to work on this task and resolve it.

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