User documentation for the managed runtime: the install -> download ->
use flow, how hardware-aware model selection works, the memory
guarantees (fit pills, context growth, the 64K floor), the system
resources statusbar item, the local_runtime config reference, and using
an existing llama-server instead of the managed one. Cross-linked from
configuring-models, the desktop guide, and both manual local-LLM guides
(Ollama, Mac), which stay authoritative for manual setups.
