fix(uds-auth): emergency login workspaces, Desktop key prompts, persistent sessions

Emergency (fallback / sealed-box) admins lost the workspace sidebar and saw
"sign-in failed / add API key" on DSH Desktop because the remote.mux opens
anonymously at boot and every early call was rejected terminally.

- gateway: anonymous workspace/follow reaches dsh-acl's empty baseline;
  anonymous streams are parked until the carrier aborts instead of failing;
  anonymous workspace/initializeDefault answers "nothing created"
- request-auth: a dead UDS_SESSION cookie no longer shadows a valid WS ticket
  or bridge (sync + async variants used by all callers)
- dsh-acl: /api/* waits (bounded 15s) for the gateway ACL during Host startup
  instead of 403, so the Desktop welcome read no longer fails
- desktop-bootstrap: key/account projection is best-effort per reference
- client: emit connection/reset after login so boot-time caches (settings
  describe mirror -> Settings > Models) re-read under the real principal
- sessions: absolute lifetime fixed at 7 days (was min(ttl, 7d) = 30 min);
  bridge expiry slides with its session; MemoryStore persisted to
  sessions.json (bearer hash only, userData AES-256-GCM sealed)
- README: session lifetime/persistence and DSH compatibility notes

Also includes previously uncommitted uds-auth 0.3.x work in this tree.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

uds-auth/lib/identity-cache.js

@@ -1,22 +1,16 @@
 /**
- * Last verified browser identity (bridge or cookie).
- * Desktop mux follow/history often runs with empty ALS; fall back here after
- * a successful /uds-auth HTTP auth or WS upgrade bind.
+ * Deprecated global last-user cache (SEC-06).
+ * Kept as no-ops so older imports do not crash; never restores a principal.
  */
 
-/** @type {object|null} */
-let lastBrowserIdentity = null
-
-export function rememberBrowserIdentity(identity) {
-  const emp = identity?.empNo || identity?.userContext?.empNo
-  if (!emp) return
-  lastBrowserIdentity = identity
+export function rememberBrowserIdentity(_identity) {
+  /* intentionally no-op — connection-bound identity only */
 }
 
 export function clearBrowserIdentity() {
-  lastBrowserIdentity = null
+  /* intentionally no-op */
 }
 
 export function peekBrowserIdentity() {
-  return lastBrowserIdentity
+  return null
 }