Implementation-level spec for the hyperguild CLI: a stdlib Go binary
at cmd/hyperguild/ with subcommands tier, brain query/write, and mode
(cloud|client-local|sovereign). Replaces the supervisor's tier MCP and
provides shell-friendly access to the brain HTTP REST API.
Six measurable success criteria, seven out-of-scope items, six risks.
Decisions logged: stdlib flag + inline router (no cobra), reuse
internal/tier verbatim, BRAIN_URL env override, mode subcommand writes
.mcp.json with per-mode template plus placeholder for the Plan 6
routing pod.
