Buzz Desktop v0.4.23

• fix(desktop): strip GIF metadata extensions before upload (#2425) (47d7eb698)
• feat(desktop): gate sign-out behind key backup + typed confirmation (#2424) (fd967c6ea)
• feat(desktop+acp): spawn a harness per (agent, community) pair at GUI startup — warm sockets, lazy LLM pool (#2122) (61cc738ee)
• Show team count separately in channel template rows (#2404) (6d04d279a)
• fix(onboarding): skip community profile setup for existing relay members (#2300) (25f631870)
• Unify sidebar chrome across themes (#2380) (f8fd055b9)
• fix(desktop): refresh cached channel member names (#2258) (5a3b8176a)