profile: wire bio/phone/location/timezone to arcadia

Adds a "Profile" card backed by /api/v1/profile (PATCH) for the four
public-profile fields arcadia already had columns for. Bio moved out of
local prefs (the server one supersedes); local prefs keeps only title,
signature, defaultAgentId, and the avatar URL mirror.

Save/revert mirror the existing Account card's pattern. The new fields
get arcadia validation + audit logging for free.

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

app/lib/profile.ts

@@ -1,12 +1,13 @@
-// Local user preferences — title, bio, signature, avatar, default agent.
-// Persisted in localStorage; reactive across tabs. Identity (name, email)
-// is owned by the arcadia session, not this store — see ~/lib/session.ts.
+// Local user preferences — title, signature, default agent, plus a cache
+// mirror of the resolved avatar URL. Persisted in localStorage; reactive
+// across tabs. Identity (name, email) is owned by the arcadia session
+// (~/lib/session.ts); the public profile (bio, phone, location, timezone)
+// is server-backed via /api/v1/profile (~/lib/arcadia/profiles.ts).
 
 import { useEffect, useSyncExternalStore } from "react"
 
 export type Profile = {
   title: string
-  bio: string
   signature: string
   avatarUrl: string
   defaultAgentId: string
@@ -14,7 +15,6 @@ export type Profile = {
 
 export const DEFAULT_PROFILE: Profile = {
   title: "",
-  bio: "",
   signature: "",
   avatarUrl: "",
   defaultAgentId: "",
@@ -32,7 +32,6 @@ function readFromStorage(): Profile {
     return {
       title:
         typeof parsed.title === "string" ? parsed.title : DEFAULT_PROFILE.title,
-      bio: typeof parsed.bio === "string" ? parsed.bio : DEFAULT_PROFILE.bio,
       signature:
         typeof parsed.signature === "string"
           ? parsed.signature