fix(auth): keep the failure path total, and align the docs with the new order (#2144)

Copilot review round 14. Two code fixes and a documentation sweep.

- `buildRevocationRequest` ran outside `revokeToken`'s best-effort try.
  `encodeURIComponent` throws on a lone UTF-16 surrogate — valid JSON, so it
  can reach there from a persisted client id or secret — and every caller has
  already cleared its local state by then, so a rejection instead of a `failed`
  outcome would break the documented guarantee. Construction is inside the try
  now, and the catch reports `params.endpoint` rather than a `url` that may not
  exist on that path.
- The fixture's Basic decode turned a malformed percent escape into an Express
  500, reporting a bad credential as a server fault rather than as the
  `invalid_client` 401 the endpoint means. Decoding failure is failed
  authentication.
- Ten places still said revocation happens *before* the clear, which the
  reorder in the previous commit made false: the settings-form description, the
  `--no-revoke` help text, both READMEs, `docs/mcp-server-configuration.md`,
  three JSDoc blocks, and the PR body. Swept, and the ordering is stated where
  it is load-bearing rather than asserted in passing. Also merged the two
  adjacent JSDoc blocks on `InspectorClient.clearOAuthTokens`.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0177mPHAdECD18nLLCTwR5rh
Signed-off-by: cliffhall <cliff@futurescale.com>

core/mcp/oauthManager.ts

@@ -497,8 +497,8 @@ export class OAuthManager {
   }
 
   /**
-   * Revoke the grant at the authorization server (RFC 7009), then drop the
-   * local OAuth state.
+   * Drop this server's local OAuth state, and revoke the grant at the
+   * authorization server (RFC 7009).
    *
    * The order is **snapshot → clear → revoke**, and it matters. Everything the
    * requests need is read out of the store first, because the clear empties it;