feat(voice): support per-client conversation mode state

packages/ui/src/lib/client-identity.ts

@@ -0,0 +1,58 @@
+const CLIENT_ID_STORAGE_KEY = "codenomad.client-id"
+const CONNECTION_ID_STORAGE_KEY = "codenomad.connection-id"
+
+let cachedClientId: string | null = null
+let cachedConnectionId: string | null = null
+
+export function getClientIdentity(): { clientId: string; connectionId: string } {
+  return {
+    clientId: getOrCreateClientId(),
+    connectionId: getOrCreateConnectionId(),
+  }
+}
+
+function getOrCreateClientId(): string {
+  if (cachedClientId) return cachedClientId
+  cachedClientId = getOrCreateStoredValue(CLIENT_ID_STORAGE_KEY, window.localStorage)
+  return cachedClientId
+}
+
+function getOrCreateConnectionId(): string {
+  if (cachedConnectionId) return cachedConnectionId
+  cachedConnectionId = getOrCreateStoredValue(CONNECTION_ID_STORAGE_KEY, window.sessionStorage)
+  return cachedConnectionId
+}
+
+function getOrCreateStoredValue(key: string, storage: Storage): string {
+  if (typeof window === "undefined") {
+    return generateUUID()
+  }
+
+  try {
+    const existing = storage.getItem(key)
+    if (existing && existing.trim()) {
+      return existing.trim()
+    }
+  } catch {
+    return generateUUID()
+  }
+
+  const next = generateUUID()
+  try {
+    storage.setItem(key, next)
+  } catch {
+    // Ignore storage failures and fall back to the in-memory value.
+  }
+  return next
+}
+
+function generateUUID(): string {
+  if (typeof crypto !== "undefined" && crypto.randomUUID) {
+    return crypto.randomUUID()
+  }
+  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, (char) => {
+    const random = (Math.random() * 16) | 0
+    const value = char === "x" ? random : (random & 0x3) | 0x8
+    return value.toString(16)
+  })
+}