IAM auto-bootstrap could get permanently stuck in a half-done state:
_seed_tables wrote the workspace first, so any_workspace_exists()
returned true on restart even when user/key/signing-key creation had
failed. Remove workspace creation from _seed_tables (WorkspaceInit
handles it) and use any_signing_key_exists() as the completion check
since the signing key is the last thing written.
Run pre-service initialisers (PulsarTopology) in start() before
opening pub/sub connections, breaking the chicken-and-egg where the
bootstrapper needed Pulsar namespaces that it was responsible for
creating. Guard against empty cluster list when broker isn't ready.
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