Function completeLogin

completeLogin(
    code: string,
    pending: PendingLogin,
    config: OidcConfig,
    provider: OidcProvider,
    nowMs: number,
    deps: OidcDeps,
): Promise<{ claims: IdTokenClaims } | { refusal: string }>
Exchanges the code and verifies what comes back.

The awaits run before PHP is entered, so PHP never has to suspend.
Parameters
- code: string
- pending: PendingLogin
- config: OidcConfig
- provider: OidcProvider
- nowMs: number
- deps: OidcDeps
Returns Promise<{ claims: IdTokenClaims } | { refusal: string }>
- Defined in src/ops/oidc.ts:439