Ports the in-repo KEYSAT_AGENT_GUIDE.md into the docs site as a
first-class page rather than linking out to a raw markdown file on
GitHub. The page covers authentication, scoped API keys, OpenAPI
discovery, error envelope conventions, common workflows (issue /
revoke / find / cancel / change-tier / free-machine), webhook
event types + signature verification, robust-agent patterns, a
"comp-license-via-email" recipe, and the operator-only
operations that aren't exposed to any scoped key.
Sidebar gains an "Agent integration" entry under Get started on
every page (index, install, integrate, wire-format, operate, agent
itself). Docs index "These docs cover" + "Where to next" grids
each gain a third card pointing at the agent guide so it's
discoverable from the introduction page even for visitors who
don't scan the sidebar.
The left sidebar already covers Install / Integrate / Wire format /
Operate across its four groups (Get started, Concepts, Reference,
Operate). The top-right nav duplicated those links one level up. On
mobile it was already hidden via @media rule, so the sidebar was
always the canonical navigation. Now it's the only navigation —
cleaner topbar, no duplication.
Standard docs-site convention: top-left brand goes to the marketing
home, the 'Docs' badge next to it signals you're in the docs section.
The separate 'Marketing' nav item is no longer needed once the brand
itself handles that link.
Keysat