Fix HMR breaking after vite server restarts

[AlecAivazis]

When vite restarts the dev server (config change, lockfile change, pressing r), HMR would break until the dev server was manually restarted, failing on every save with:

[houdini] HMR pipeline error: Error: database is not open

Vite creates the replacement server before closing the old one, and two things went wrong in that window:

1. Compiler ownership: the dev compiler lived in a module-level export let compiler in vite/hmr.ts. By the time the old server's close handler ran, that binding pointed at the replacement's compiler, so the old server shut down the new server's compiler and database connection.

2. Session overlap: the new session wiped and recreated the orchestration database while the old session's plugin processes were still running. Plugin registration collided with leftover rows (UNIQUE constraint failed: plugins.name), and since the Go side treated that as fatal, the fresh plugin died and the orchestrator was left dialing a port nobody listens on (ECONNREFUSED).

[changeset-bot]

🦋 Changeset detected

Latest commit: 1506beb

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
houdini	Patch
houdini-core	Patch
houdini-svelte	Patch

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