abac42c344
summarize_all fanned out 8 concurrent workers, but the MI50 llama.cpp server runs
a single slot (--parallel 1). Firing 8 at once queued them, blew the client timeout
('summary retry … Request timed out'), and thrashed/cancelled the KV cache — wasted
compute and heat. Concurrency is now backend-aware: 8 for cloud, 1 for local/MI50.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>