feat(sso): IEsiTokenRefreshSink.OnRefreshFailedAsync

[seraphx2]

What

Adds a failure hook to IEsiTokenRefreshSink: OnRefreshFailedAsync(character, exception), called when a transparent access-token refresh itself throws (refresh token revoked, expired, or the app's scopes changed). character is unchanged from before the attempt, and the triggering call still throws either way - this just gives a registered sink a chance to react (e.g. flag the character in your own store so other jobs stop querying it) before that exception propagates.

Why

Real-world need: a consumer's background jobs query many characters' data on a schedule and need to skip characters whose credentials have gone bad, rather than repeatedly failing against them. Until now there was no signal that a refresh failed at all - only the exception from whichever call happened to trigger it.

Verified

• Traced the actual failure path in SsoLogic.RefreshAccessTokenAsync - the token exchange throws before mutating character, so "character is unchanged" in the XML doc is accurate, not aspirational.
• TokenRefreshTests.FakeSink predated this interface member and didn't implement it - broke the test build (CS0535). Fixed, and added Failed_refresh_notifies_the_sink_and_still_throws, asserting: the sink's failure hook fires with the right character/exception, OnRefreshedAsync does not also fire, the exception still propagates, and the character's token/refresh-token are untouched.
• Full solution build: 0 errors, 0 warnings. Full unit suite: 49/49 passing.
• Documented in the README's DbTokenSink example (using the real CanQueryEsi-style pattern that motivated this) and in the CHANGELOG.

Notes

• No per-call (EsiCallOptions) equivalent added deliberately - a one-off caller already gets the exception directly from the failed call, so a duplicate callback would be redundant. The sink is for the DI/background-job case where nothing is already watching that call.
• Not yet released; folds into the current beta cycle.

🤖 Generated with Claude Code

[sonarqubecloud]

❌ The last analysis has failed.

See analysis details on SonarQube Cloud

[seraphx2]

Superseded — cherry-picked this commit (a356771) directly onto dev as 5b6d766 instead of merging this branch, since it had drifted well behind dev's subsequent CA1305/CA1707/CA1062/net10.0 work and a plain merge would've hit conflicts across most of the Logic files. The feature itself is now on dev and shipping in the next release. Closing this PR; branch left in place for reference.

(For the record: the SonarCloud check failure here was the scan itself erroring out — "the last analysis has failed" — not a reported code-quality issue. build/check both passed.)