Read `~/.zode/config.json` on startup (native/daemon) and merge every
Zode `(provider, model)` pair into agent_settings.builtin_agents as a
BuiltinAgentConfig, so providers already configured in the Zode CLI show
up as OpenPencil custom models without re-entering keys. Anthropic vs
OpenAI-compat is chosen by the provider `type`; one custom model per
model id (provider name qualified by model when a provider has several).
Best-effort + idempotent: missing/malformed file is a silent no-op, and
add_builtin_agent_config backend-dedupes so re-running each launch adds
nothing new. Imported agents are tracked in imported_agent_ids and
excluded from settings.json persistence — Zode's config stays the single
source of truth and its API keys are never silently duplicated onto a
second on-disk location (they're re-imported every launch).
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