convex() fails to bundle on better-auth 1.7 (oidc-provider removed)

`@convex-dev/better-auth@0.12.5` (current latest, including `main`) still declares:

```json
"peerDependencies": {
"better-auth": ">=1.6.11 <1.7.0"
}
```

`convex()` also still imports `better-auth/plugins/oidc-provider` (e.g. `dist/plugins/convex/index.js`).

Better Auth **1.7.0** (2026-08-18) removed that plugin ([release](https://github.com/better-auth/better-auth/releases/tag/v1.7.0), [upgrade guide](https://www.better-auth.com/docs/guides/1-7-upgrade-guide)). Installing `better-auth@1.7.x` makes `npx convex dev` fail at component bundling:

```
✘ [ERROR] Could not resolve "better-auth/plugins/oidc-provider"

node_modules/@convex-dev/better-auth/dist/plugins/convex/index.js:
import { oidcProvider as oidcProviderPlugin } from "better-auth/plugins/oidc-provider";

The path "./plugins/oidc-provider" is not exported by package "better-auth"
```

**Environment**

- `@convex-dev/better-auth`: `0.12.5`
- `better-auth` / `@better-auth/passkey`: `1.7.2` (broken), `~1.6.30` (works)
- Convex CLI: `1.45.0`

**Workaround**

Pin `better-auth` and `@better-auth/passkey` to `~1.6.30` (last line inside the published peer range).

Related: #344 (deprecation on 1.6), #380 (oauth-provider migration, unreviewed).

Start by inspecting the package metadata and the source that produces dist/plugins/convex/index.js, then compare the Better Auth 1.7 upgrade guide and related issues #344 and #380. Confirm how the removed oidc-provider import and peer dependency range should be handled; done means better-auth 1.7.x bundles with npx convex dev without the unresolved export error.

Written by the indexing model from the issue text.