vite-plugin isn't linted in CI

Was digging through the lint setup and noticed packages/vite-plugin doesn't actually get linted anywhere in CI. Two things going on:

- the root eslint.config.js ignores packages/vite-plugin/**, so the repo-wide `eslint .` in the format job skips it
- nothing runs the package's own lint script either. make lint / rust-client-ts-lint only cover web_store, and there's no vite-plugin lint job like the react-sdk one

Looks like it was just missed when the per-package eslint configs were first set up. react-sdk and idxdb-store both got a local config plus wiring in the initial port, but vite-plugin only got the "lint": "eslint src" script in package.json, with no config for it to use and no CI hook. So the script's been dead since day one.

I've got a small fix ready that mirrors how react-sdk is handled: a local eslint.config.js for the package, plus a vite-plugin-lint target and CI job so it actually runs. The package source is already clean, so it passes with no code changes. Want me to open a PR for it?

Look at the packages/vite-plugin directory to see its current package.json and the missing eslint.config.js. Examine how packages/react-sdk and packages/idxdb-store are set up with their own lint configs and CI jobs. The fix involves creating a similar config for vite-plugin and adding a lint target in the project's Makefile or CI configuration. Run the new lint script locally to ensure it passes without errors.

Written by the indexing model from the issue text.