create_progress_router accepts optional body detection and metering
hooks so host apps can record usage when clients POST /progress/ with
the legacy workstream_id field.
create_progress_router accepts meter_legacy_workstream_id so host apps
like state-hub can record Deprecation usage when callers filter progress
events with the legacy query param.
Add create_capability_request_write_router with host workflow callbacks,
CapabilityRequestReroute schema, HubCoreMCPServer.attach_to() with CORE_TOOL_NAMES
exclude filtering, tests, and mark HUB-WP-0002 finished.
Extract the first reusable slice (models, schemas, routers, MCP, migrations)
from state-hub with INTENT/SCOPE, agent instructions, workplan, and aligned
inter_hub capability registry index.
