llm: auto-load active config from arcadia on app boot

Adds <LlmConfigBootstrap /> in root.tsx that, when localStorage has no
active LLM settings, fetches enabled configurations from arcadia and
seeds the active settings (provider/model/baseURL/secretName + reasoning
effort) from the preferred row. Idempotent and silent on auth failure;
retries on session change.

Selection: prefer metadata.default === true, otherwise first enabled row.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/lib/llm-config-bootstrap.tsx

@@ -0,0 +1,91 @@
+// One-time bootstrap of the active LLM settings from arcadia.
+//
+// On mount (and again whenever the session changes), if the operator has no
+// active LLM settings in localStorage, fetch the tenant's enabled
+// configurations and seed the active settings from the preferred row:
+//
+//   1. Any row with `metadata.default === true` (operator-marked default).
+//   2. Otherwise the first enabled row.
+//
+// Once active settings exist, this component does nothing — the settings
+// panel remains the place to switch between configs.
+
+import { useEffect } from "react"
+import { useArcadiaClient } from "@crema/arcadia-client"
+import {
+  loadSettings,
+  saveSettings,
+  type LLMProvidersSettings,
+  type ProviderId,
+} from "@crema/llm-providers-ui"
+
+import {
+  listConfigurations,
+  saveActiveReasoning,
+  type LlmConfiguration,
+} from "~/lib/arcadia/llm-configs"
+
+const ACTIVE_KEY = "crema.llm-providers.settings"
+
+function hasActiveSettings(): boolean {
+  if (typeof window === "undefined") return false
+  return !!localStorage.getItem(ACTIVE_KEY)
+}
+
+function pickPreferred(configs: LlmConfiguration[]): LlmConfiguration | null {
+  const enabled = configs.filter((c) => c.enabled)
+  if (enabled.length === 0) return null
+  const flagged = enabled.find(
+    (c) => (c.metadata as { default?: boolean } | null)?.default === true,
+  )
+  return flagged ?? enabled[0]
+}
+
+function applyConfig(c: LlmConfiguration): void {
+  const current = loadSettings()
+  const next: LLMProvidersSettings = {
+    ...current,
+    providerId: c.provider as ProviderId,
+    model: c.model,
+    baseURL: c.base_url || undefined,
+    secretName: c.secret_name || undefined,
+  }
+  saveSettings(next)
+  saveActiveReasoning(c.reasoning_effort ?? "off")
+}
+
+export function LlmConfigBootstrap() {
+  const arcadia = useArcadiaClient()
+
+  useEffect(() => {
+    let cancelled = false
+
+    const tryBootstrap = async () => {
+      if (hasActiveSettings()) return
+      const token =
+        typeof window !== "undefined"
+          ? sessionStorage.getItem("arcadia_access_token")
+          : null
+      if (!token) return
+      try {
+        const configs = await listConfigurations(arcadia, { enabled: true })
+        if (cancelled) return
+        const pick = pickPreferred(configs)
+        if (pick && !hasActiveSettings()) applyConfig(pick)
+      } catch {
+        // 401 / network — silently skip; will retry on next session change.
+      }
+    }
+
+    void tryBootstrap()
+
+    const onSessionChange = () => void tryBootstrap()
+    window.addEventListener("crema:session-change", onSessionChange)
+    return () => {
+      cancelled = true
+      window.removeEventListener("crema:session-change", onSessionChange)
+    }
+  }, [arcadia])
+
+  return null
+}