feat(grok): convert interactive intake/secretary to the grok CLI; delete opencode

Move the last Grok runtime off opencode onto xAI's official `grok` CLI, for full
parity with the Claude path. The intake/secretary chat now runs per-turn headless
`grok -p` invocations that resume one session id (proven live: context carries
across runs), with streaming-json deltas mapped to the existing panel StreamChunk
kinds — the IntakeDriver loop, message source, relay, and idle reaper are reused
unchanged; only the SessionFactory differs (GrokCliSession replaces the
opencode-serve session).

- GrokCliSession + a pure, unit-tested streaming-json -> StreamChunk assembler
  (thought coalesced to one block, text streamed live, end captures the session
  id for -r, fenced-draft fallback, clear errors incl. rate-limit).
- intake propose_draft and secretary read_company_state/read_task/submit_directive
  are now FastMCP servers (roboco-intake / roboco-secretary) wired into
  ~/.grok/config.toml, launched via `uv run --directory /app` to resolve the
  installed package. The secretary tools reuse the shared backend helpers.
- Orchestrator: interactive spawn mounts the subscription auth + per-agent usage
  dir (no metered xAI key, no permission env — grok flags carry per-role perms);
  usage/cost now read a captured usage.json (drop the opencode.db reader, the
  _opencode_db_path/_grok_usage_from_opencode methods, and the cost-cap's
  opencode read). hosts["opencode"] -> hosts["grok_usage"]; OPENCODE_DATA_DIR ->
  GROK_USAGE_DATA_DIR.
- Fix one-shot usage capture: `-s` does not pin the session id (grok generates
  its own), so the entrypoint now reads the real id back from the JSON run log
  and the reader uses it; usage is captured per-turn on the interactive path.
- Delete the opencode layer: opencode_config/opencode_usage/opencode_session, the
  docker/grok/*.js plugins, the old one-shot entrypoint, and their tests.
- Compose (all three files), .env.example, and stale comments updated to the
  grok-CLI runtime; add the SuperGrok auth mount + grok-usage dir.

Gate green: ruff, mypy (296 files), xenon, tests. NAS build/verify pending.

roboco/mcp/secretary_server.py

@@ -0,0 +1,64 @@
+"""roboco-secretary MCP server — the Secretary's CEO-authority tools.
+
+Parity with the Claude Secretary's SDK tools
+(:func:`roboco.agent_sdk.secretary_driver.build_secretary_options`):
+``read_company_state`` / ``read_task`` (reads) and ``submit_directive`` (acts).
+Each calls the backend ``/api/secretary/*`` routes with the container's HMAC
+agent token; the backend gate-list queues high-impact directive kinds for the
+CEO's confirmation and runs low-risk ones directly. The backend-calling logic is
+reused verbatim from ``secretary_driver`` (the SDK and grok paths share one
+HTTP seam), so this server only wraps those helpers as MCP tools.
+
+Wired into ``~/.grok/config.toml`` by ``grok_secretary_main``; the container
+provides ``ROBOCO_API_URL`` / ``ROBOCO_AGENT_ID`` / ``ROBOCO_AGENT_ROLE`` /
+``ROBOCO_AGENT_TOKEN`` (the same auth substrate the one-shot Grok path uses).
+"""
+
+from __future__ import annotations
+
+import json
+from typing import Any
+
+from mcp.server.fastmcp import FastMCP
+
+from roboco.agent_sdk.secretary_driver import (
+    _do_read_state,
+    _do_read_task,
+    _do_submit_directive,
+)
+
+mcp = FastMCP("roboco-secretary")
+
+
+@mcp.tool()
+async def read_company_state() -> str:
+    """Read a compact snapshot of company state.
+
+    The charter (goals), task counts by status, pending pitches, and any
+    directives awaiting the CEO's confirmation.
+    """
+    return json.dumps(await _do_read_state())
+
+
+@mcp.tool()
+async def read_task(task_id: str) -> str:
+    """Read one task's detail by its id."""
+    return json.dumps(await _do_read_task(task_id))
+
+
+@mcp.tool()
+async def submit_directive(kind: str, payload: dict[str, Any]) -> str:
+    """Act on the CEO's command.
+
+    'kind' is one of: relay_message (payload: channel, text), update_charter
+    (payload: charter), control_task (payload: task_id, action[start|cancel|
+    override], status?), approve_pitch (payload: pitch_id, notes?), announce
+    (payload: text). High-impact kinds (charter, control_task, approve_pitch,
+    announce) are queued for the CEO's explicit confirmation; relay_message runs
+    directly.
+    """
+    return json.dumps(await _do_submit_directive(kind, payload or {}))
+
+
+if __name__ == "__main__":
+    mcp.run()