fix(auth): new OAuth accounts invisible to scheduler after dynamic registration

When new OAuth auth files are added while the service is running,
`applyCoreAuthAddOrUpdate` calls `coreManager.Register()` (which upserts
into the scheduler) BEFORE `registerModelsForAuth()`. At upsert time,
`buildScheduledAuthMeta` snapshots `supportedModelSetForAuth` from the
global model registry — but models haven't been registered yet, so the
set is empty. With an empty `supportedModelSet`, `supportsModel()`
always returns false and the new auth is never added to any model shard.

Additionally, when all existing accounts are in cooldown, the scheduler
returns `modelCooldownError`, but `shouldRetrySchedulerPick` only
handles `*Error` types — so the `syncScheduler` safety-net rebuild
never triggers and the new accounts remain invisible.

Fix:
1. Add `RefreshSchedulerEntry()` to re-upsert a single auth after its
   models are registered, rebuilding `supportedModelSet` from the
   now-populated registry.
2. Call it from `applyCoreAuthAddOrUpdate` after `registerModelsForAuth`.
3. Make `shouldRetrySchedulerPick` also match `*modelCooldownError` so
   the full scheduler rebuild triggers when all credentials are cooling
   down — catching any similar stale-snapshot edge cases.

sdk/cliproxy/service.go

@@ -312,6 +312,12 @@ func (s *Service) applyCoreAuthAddOrUpdate(ctx context.Context, auth *coreauth.A
 	// This operation may block on network calls, but the auth configuration
 	// is already effective at this point.
 	s.registerModelsForAuth(auth)
+
+	// Refresh the scheduler entry so that the auth's supportedModelSet is rebuilt
+	// from the now-populated global model registry. Without this, newly added auths
+	// have an empty supportedModelSet (because Register/Update upserts into the
+	// scheduler before registerModelsForAuth runs) and are invisible to the scheduler.
+	s.coreManager.RefreshSchedulerEntry(auth.ID)
 }
 
 func (s *Service) applyCoreAuthRemoval(ctx context.Context, id string) {