fix(core): add vite server fallback for embedded connections

[webfansplz]

The embedded client currently loads connection metadata from the page origin. When the page is served by a separate backend, this can point to the wrong server.

This PR:

keeps the existing /__devtools/ base as the first candidate

falls back to the vite server URL inferred from import.meta.url

preserves existing same-origin and proxied setups

adds unit tests for both candidate URLs and their priority

Related devframe change

This relies on devframes/devframe#146.

fetch() resolves normally for HTTP errors such as 404. If the response body is valid JSON, the previous implementation could treat it as connection metadata and never try the fallback URL.

devframes/devframe#146 checks response.ok before parsing the response, allowing connection discovery to continue with the next candidate after an HTTP error.

Fixes #489.

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commit: 20215b7

[Copilot]

Pull request overview

This PR fixes embedded-client connection discovery when the host page is served from a different origin than the Vite dev server by adding a fallback base URL derived from import.meta.url, while keeping the existing /__devtools/ lookup as the first (backwards-compatible) candidate.

Changes:

• Update the injected runtime to try connection metadata from /__devtools/ first, then fall back to the Vite-origin URL inferred from import.meta.url.
• Add unit tests asserting the two candidate base URLs and their priority order.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/core/src/client/inject/runtime.ts	Adds baseURL fallback logic for RPC client connection discovery in embedded mode.
packages/core/src/client/inject/runtime.test.ts	Introduces tests covering the baseURL candidate list and its ordering.

Comments suppressed due to low confidence (2)

packages/core/src/client/inject/runtime.test.ts:44

• This assertion hardcodes '/__devtools/'. Prefer asserting against DEVTOOLS_MOUNT_PATH so the test stays consistent with the runtime constant.

    expect(options.baseURL).toHaveLength(2)
    expect(options.baseURL[0]).toBe('/__devtools/')
  })

packages/core/src/client/inject/runtime.test.ts:51

• This assertion also hardcodes the mount path. Using DEVTOOLS_MOUNT_PATH here avoids duplicated literals and keeps the fallback URL test aligned with the runtime constant.

    expect(options.baseURL[1]).toBe(
      new URL('/__devtools/', import.meta.url).href,
    )

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