Operability surface and the bulk of the jopts→fopts migration:
* --log-level error|warn|info|debug + WEKNORA_LOG_LEVEL env, wired to
the SDK via client.SetDebugLevel. Invalid --log-level returns FlagError
(exit 2).
* kb status <kb-id> / kb check <kb-id> verb split (1 HTTP vs 1+N for
failed_count aggregation).
* agent status <agent-id> / agent check <agent-id> verb split
(probes kb_scope_all_reachable via 1+N HTTP).
* kb create <name> positional (matches agent create).
* Positional id help strings namespaced (<kb-id> / <agent-id>).
* All auth / context / link / doctor / kb / agent CRUD commands migrated
to the FormatOptions API.
* root.go Execute(ctx) takes a context so signal-cancellation propagates
via cmd.Context() into long-running commands.
* Pagination termination uses len(accum) >= total (not page*pageSize)
so server-capped page sizes do not truncate aggregations.
nullkey