Copilot review (#2287), three findings:
1. **invalid-client recovery lost the provenance.** SDK v2 `auth()` answers
`invalid_client` / `unauthorized_client` with `invalidateCredentials("client")`
and an immediate retry; our clear drops the registration *and* its kind, so
the retry's URL-based client-ID save landed with nothing recorded and was
stored as `dcr`. Provenance now lives in `cimdClientMetadataUrl`, an
issuer-keyed marker on the issuer slot that records a property of the AS
rather than a credential — `clearClientInformation` deliberately leaves it
alone. `ensureCimdClientRegistration` writes it, and withdraws it when the AS
stops advertising CIMD, on every connect.
2. **Discovery became a hard network dependency.** Moving the existing-client
check after discovery meant a well-known outage could fail a reconnect the SDK
would have served from its persisted discovery state. Reuse
`provider.discoveryState()` first, and treat a discovery failure as "skip
pre-registration" rather than an error — this helper is an optimization over
what `auth()` does for itself.
3. **Dropped an unjustified double cast** in the test fetch helper; the async
signature is directly assignable to `typeof fetch`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lmj6X2epWpPE7ScdSKQmtA
Signed-off-by: cliffhall <cliff@futurescale.com>
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