init: arcadia-admin — admin webapp for arcadia-core, cloned from vibespace

Initial commit. Spun up via the docs/STARTER.md recipe: cp from vibespace,
reset git, rename package, set brand to "Arcadia Admin" with Shield icon
in app/lib/identity.ts.

Inherits the full Crema sibling-lib wiring including @crema/arcadia-client
(typed HTTP + Phoenix Channels realtime against arcadia-core) and
@crema/arcadia-auth-ui (login/signup/password-reset/2FA forms). The /login
route already renders <LoginForm>; <ArcadiaProvider> in app/root.tsx reads
VITE_ARCADIA_URL (default localhost:4000) and VITE_ARCADIA_TENANT (default
"default").

CLAUDE.md and README rewritten to frame this as the admin app for
arcadia-core. docs/STARTER.md removed — arcadia-admin is a leaf consumer,
not a downstream starter.

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

app/lib/agents.ts

@@ -0,0 +1,153 @@
+// Agent personas — named, role-scoped sub-system prompts.
+// Each persona stacks on top of the main systemPrompt to specialize the
+// assistant for a task. Persisted in localStorage; reactive across tabs.
+
+import { useEffect, useSyncExternalStore } from "react"
+
+export type Agent = {
+  id: string
+  name: string
+  role: string
+  prompt: string
+}
+
+export const DEFAULT_AGENTS: Agent[] = [
+  {
+    id: "generalist",
+    name: "Atlas",
+    role: "Generalist",
+    prompt:
+      "You handle anything: chat, planning, summaries, casual questions. Match the user's tone. Keep replies as long as the task deserves — terse for quick questions, detailed when explaining.",
+  },
+  {
+    id: "coder",
+    name: "Forge",
+    role: "Software engineer",
+    prompt:
+      "You are a senior software engineer. Write idiomatic, well-typed code. Prefer concrete examples over abstract advice. When asked to fix a bug, identify root cause before patching. Use markdown code blocks with language tags. Mention edge cases briefly when relevant.",
+  },
+  {
+    id: "writer",
+    name: "Inkwell",
+    role: "Writer",
+    prompt:
+      "You are a prose writer. Produce vivid, well-paced text — short stories, copy, emails, essays. Vary sentence length. Show, don't tell. When the user asks for a draft, deliver the draft, not a description of it.",
+  },
+  {
+    id: "researcher",
+    name: "Pilot",
+    role: "Researcher",
+    prompt:
+      "You are a careful researcher. Structure answers as: claim → evidence → caveat. Distinguish what is well-established from what is uncertain. Refuse to fabricate citations — if you don't know, say so.",
+  },
+  {
+    id: "ui-driver",
+    name: "Cursor",
+    role: "UI Operator",
+    prompt:
+      "You specialize in driving this app's UI on the user's behalf. Prefer doing over explaining. When the user asks for an action, emit an action block immediately. When they ask a question about the app, answer concisely and offer to do it.",
+  },
+]
+
+const STORAGE_KEY = "crema.agents"
+const ACTIVE_KEY = "crema.assistant.activeAgent"
+const CHANGE_EVENT = "crema:agents-change"
+
+function isAgent(v: unknown): v is Agent {
+  return (
+    !!v &&
+    typeof v === "object" &&
+    typeof (v as Agent).id === "string" &&
+    typeof (v as Agent).name === "string" &&
+    typeof (v as Agent).role === "string" &&
+    typeof (v as Agent).prompt === "string"
+  )
+}
+
+function readFromStorage(): Agent[] {
+  if (typeof window === "undefined") return DEFAULT_AGENTS
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY)
+    if (!raw) return DEFAULT_AGENTS
+    const parsed = JSON.parse(raw)
+    if (!Array.isArray(parsed)) return DEFAULT_AGENTS
+    const cleaned = parsed.filter(isAgent)
+    return cleaned.length > 0 ? cleaned : DEFAULT_AGENTS
+  } catch {
+    return DEFAULT_AGENTS
+  }
+}
+
+export function loadAgents(): Agent[] {
+  return readFromStorage()
+}
+
+export function saveAgents(next: Agent[]) {
+  if (typeof window === "undefined") return
+  localStorage.setItem(STORAGE_KEY, JSON.stringify(next))
+  window.dispatchEvent(new CustomEvent(CHANGE_EVENT))
+}
+
+export function resetAgents() {
+  saveAgents(DEFAULT_AGENTS)
+}
+
+let cached: Agent[] | null = null
+
+function subscribe(cb: () => void): () => void {
+  const onChange = () => {
+    cached = null
+    cb()
+  }
+  window.addEventListener(CHANGE_EVENT, onChange)
+  window.addEventListener("storage", (e) => {
+    if (e.key === STORAGE_KEY || e.key === ACTIVE_KEY) onChange()
+  })
+  return () => {
+    window.removeEventListener(CHANGE_EVENT, onChange)
+  }
+}
+
+function getSnapshot(): Agent[] {
+  if (!cached) cached = readFromStorage()
+  return cached
+}
+
+function getServerSnapshot(): Agent[] {
+  return DEFAULT_AGENTS
+}
+
+export function useAgents(): Agent[] {
+  const value = useSyncExternalStore(subscribe, getSnapshot, getServerSnapshot)
+  useEffect(() => {
+    cached = null
+  }, [])
+  return value
+}
+
+export function loadActiveAgentId(): string {
+  if (typeof window === "undefined") return DEFAULT_AGENTS[0].id
+  try {
+    return localStorage.getItem(ACTIVE_KEY) ?? DEFAULT_AGENTS[0].id
+  } catch {
+    return DEFAULT_AGENTS[0].id
+  }
+}
+
+export function saveActiveAgentId(id: string) {
+  if (typeof window === "undefined") return
+  localStorage.setItem(ACTIVE_KEY, id)
+  window.dispatchEvent(new CustomEvent(CHANGE_EVENT))
+}
+
+export function composeSystemPrompt(
+  base: string,
+  agent: Agent | undefined,
+): string {
+  if (!agent) return base
+  return `${base}\n\nActive persona: ${agent.name} — ${agent.role}\n${agent.prompt}`
+}
+
+export function newAgentId(): string {
+  return `agent-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 6)}`
+}