docker/hsp:claude-kit-latest

HSP-capable variant of the built-in `claude` sandbox kit -- the same `claude` CLI (stock `--dangerously-skip-permissions` entrypoint, no fork, no research-preview flags, pinned to 2.1.287), plus an organization-managed Claude Code *mod* (this repo's `claude/mod`, loaded from a root-owned directory marketplace via managed settings) that runs a child shim (this repo's `claude/src/shim.ts`) exposing the Harness Steering Protocol (hsp/1): the shim serves `$HSP_SOCKET`, and hands each accepted steer back to the mod, which injects it into the conversation (`$.session.append` mid-turn, `$.prompt.submit` when idle). Built to test/demo the Agentic Platform's custom-kit-only HSP capability (APT-1293/APT-1382). Everything below this point through `agentInstructions` is copied verbatim from the built-in `claude` kit spec (docker/sandboxes, sandboxlib/agentkits/agents/claude/spec.yaml) -- see this repo's claude/README.md ("Claude Code adapter and sandbox kit: claude-hsp-kit"), for the diff summary; the only changes are this description, `sandbox.image`, `sandbox.entrypoint`, `name`, `displayName`, and the `extraKnownMarketplaces`/`enabledPlugins`/`appendPlugins` keys baked into `/etc/claude-code/managed-settings.json` at image build time (claude/kit/Dockerfile). Note: the mod loads in every session launched from this image, but is a no-op unless the platform set `$HSP_SOCKET` (HSP spec 4.2). Unlike the previous settings-hook design there is no `crossSessionInbound` key any more: nothing writes to Claude Code's cross-session inbox socket.