fix: detect eve dev-server readiness url

[mwln]

Summary

was having issues with other urls appearing in dev server startup being caught
via the regex check and then proxying requests there that should be going to the eve agent.

Example

$ vite dev
✓ Compiled workflows in 429ms (32 steps, 3 workflows)
☰eve  v0.49.0
node_modules/@vercel/otel/dist/node/index.js (23:28893) [EVAL] Use of direct `eval` function is strongly discouraged as it poses security risks and may cause issues with minification.
 - Use of direct `eval` here. in node_modules/@vercel/otel/dist/node/index.js at 254579..254583
  │
  │ Help: Consider using indirect eval. For more information, check the documentation: https://rolldown.rs/guide/troubleshooting#avoiding-direct-eval


  VITE v8.2.2  ready in 2621 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help

this would fail and write the following to sveltekit-dev-server.json file:

{
  "appRoot": "example/dir",
  "origin": "https://rolldown.rs",
  "pid": 12345,
  "updatedAt": "2026-09-04T00:00:00.000Z"
}

another signal is the fact that the application dev server which is proxying to the agent starts up after this, signaling that it "found" the URL in the startup and doesn't need to wait any more. The actual eve dev startup happens some time a little later with the URL we actually need to await.

[DEV] server listening at http://127.0.0.1:50036/

Validation

• confirmed that this was the case by writing RED tests for general https:// urls against the dev server startup
• wrote a more robust regex check which is rooted against the /server listening at/ substring from the eve cli
• confirmed this worked through GREEN tests

Checklist

• This change was requested or approved by a maintainer
• I ran the relevant checks from CONTRIBUTING.md
• I added tests and documentation where relevant
• I added a changeset if this touches the published eve package
• DCO sign-off passes for every commit (git commit --signoff)

[vercel]

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