Add create-workstream: MCP tool, CLI commands, dashboard hint

MCP server: add create_workstream(topic_id, title, slug?, owner?,
  description?, due_date?) — auto-generates slug from title if omitted;
  emits workstream_created progress event. Now 12 tools total.

CLI: add two new subcommands —
  custodian create-workstream --domain DOMAIN --title TITLE [--slug] [--owner] [--description]
  custodian create-task --workstream ID_OR_SLUG --title TITLE [--priority] [--assignee]
  create-task accepts workstream UUID or slug (resolves via API).

Dashboard: hint box below "Open Workstreams by Domain" chart listing
  registered domains that have zero workstreams, with the exact
  custodian create-workstream command to run.

TOOLS.md: updated tool count (11 → 12) and added create_workstream row.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

mcp_server/server.py

@@ -7,6 +7,7 @@ from __future__ import annotations
 
 import json
 import os
+import re
 import sys
 from datetime import datetime
 from typing import Any
@@ -156,6 +157,47 @@ def get_recent_progress(limit: int = 20, since: str | None = None) -> str:
 # Mutate tools
 # ---------------------------------------------------------------------------
 
+@mcp.tool()
+def create_workstream(
+    topic_id: str,
+    title: str,
+    slug: str | None = None,
+    description: str | None = None,
+    owner: str | None = None,
+    due_date: str | None = None,
+) -> str:
+    """Create a new workstream under a topic and emit a progress_event.
+
+    Args:
+        topic_id: UUID of the parent topic
+        title: workstream title
+        slug: URL-friendly identifier (auto-generated from title if omitted)
+        description: optional longer description
+        owner: optional owner name
+        due_date: optional ISO date string (YYYY-MM-DD)
+    """
+    if not slug:
+        slug = re.sub(r"[^a-z0-9]+", "-", title.lower()).strip("-")
+    ws = _post("/workstreams", {
+        "topic_id": topic_id,
+        "title": title,
+        "slug": slug,
+        "description": description,
+        "owner": owner,
+        "due_date": due_date,
+        "status": "active",
+    })
+    _post("/progress", {
+        "topic_id": topic_id,
+        "workstream_id": ws["id"],
+        "event_type": "workstream_created",
+        "summary": f"Workstream created: {title}",
+        "author": "custodian",
+        "detail": {"owner": owner, "slug": slug},
+    })
+    return json.dumps(ws, indent=2)
+
+
 @mcp.tool()
 def create_task(
     workstream_id: str,