Fix boot active-server selection and titlebar peer chip

Stop overwriting the header on every parallel restore connect; wait for
the last-used peer before falling back; avoid persisting temporary
active selection so the remembered server stays correct across restarts.

client/manager.js

@@ -315,20 +315,52 @@ export class ConnectionManager extends EventEmitter {
   }
 
   /**
+   * Mark a connected peer as the UI/RPC active server.
    * @param {string} id
+   * @param {{ persist?: boolean }} [opts]
+   *   persist (default true): write last-active to peers.json / localStorage.
+   *   Use persist:false for temporary boot fallback so a faster sibling peer
+   *   does not overwrite the user's real last-used server.
    */
-  setActive(id) {
+  setActive(id, opts = {}) {
     const conn = this.connections.get(id)
     if (!conn) return
     this.active = conn
-    try {
-      setLastActivePeerId(id)
-    } catch {
-      // ignore persist failures
+    const persist = opts.persist !== false
+    if (persist) {
+      try {
+        setLastActivePeerId(id)
+      } catch {
+        // ignore persist failures
+      }
     }
     this.emit('active', conn)
   }
 
+  /**
+   * Human label for header / fleet: alias when known, else short peer id.
+   * @param {string|null|undefined|{ id?: string, alias?: string|null }} idOrConn
+   * @returns {string}
+   */
+  resolvePeerLabel(idOrConn) {
+    if (idOrConn == null) return 'peer'
+    const id =
+      typeof idOrConn === 'string'
+        ? idOrConn
+        : String(idOrConn.id || idOrConn.publicKeyHex || '').slice(0, 12)
+    if (!id) return 'peer'
+    const live = this.connections.get(id)
+    const recon = this._reconnect.get(id)
+    const alias = String(
+      (typeof idOrConn === 'object' && idOrConn.alias) ||
+        live?.alias ||
+        recon?.alias ||
+        ''
+    ).trim()
+    if (alias) return alias
+    return `Peer ${String(id).slice(0, 6)}…`
+  }
+
   /**
    * Close a live connection.
    *

client/peerActive.js

@@ -0,0 +1,55 @@
+/**
+ * Active-server selection helpers (boot restore / peer switch).
+ * Pure functions — safe for unit tests without DOM or DHT.
+ */
+
+/**
+ * Loose id match: equal, or either is a prefix of the other (12-char vs longer).
+ * @param {string} a
+ * @param {string} b
+ */
+export function topicIdsMatch(a, b) {
+  if (!a || !b) return false
+  const x = String(a)
+  const y = String(b)
+  return x === y || x.startsWith(y) || y.startsWith(x)
+}
+
+/**
+ * Prefer last-known active peer if connected; otherwise first connected in list order.
+ * @param {string|null|undefined} lastActiveId
+ * @param {string[]} orderedKeys
+ * @param {Record<string, { peer?: { connected?: boolean, id?: string }|null }>} table
+ * @returns {string|null}
+ */
+export function pickPreferredActivePeer(lastActiveId, orderedKeys, table = {}) {
+  const keys = Array.isArray(orderedKeys) ? orderedKeys : []
+  if (lastActiveId) {
+    const match = keys.find(
+      (k) => topicIdsMatch(k, lastActiveId) && table[k]?.peer?.connected
+    )
+    if (match) return match
+    for (const k of keys) {
+      const peer = table[k]?.peer
+      if (peer?.connected && topicIdsMatch(peer.id, lastActiveId)) return k
+    }
+  }
+  const firstLive = keys.find((k) => table[k]?.peer?.connected)
+  return firstLive || null
+}
+
+/**
+ * Sort peer ids so last-active is first (stable for the rest).
+ * @param {string[]} keys
+ * @param {string|null|undefined} lastActiveId
+ * @returns {string[]}
+ */
+export function orderPeersForBoot(keys, lastActiveId) {
+  const list = [...(keys || [])]
+  if (!lastActiveId) return list
+  return list.sort((a, b) => {
+    if (topicIdsMatch(a, lastActiveId)) return -1
+    if (topicIdsMatch(b, lastActiveId)) return 1
+    return 0
+  })
+}