Problem
Cascade's `cascade_timeline` and `cascade_actors` MCP tools duplicate query logic that journalism-investigation's `investigation_timeline` and `investigation_entities` tools will provide. After the type inheritance refactor, Cascade tools should delegate to the base implementations and add Cascade-specific filters (capture_lane, era, chapters).
Scope
`cascade_timeline` → wraps `investigation_timeline` + adds `capture_lane` filter
`cascade_actors` → wraps `investigation_entities` + adds `era`, `tier` filters
`cascade_network` → wraps `investigation_network` (no changes needed)
Cascade-only tools (`solidarity_timeline`, `cascade_capture_lanes`, `solidarity_infrastructure_types`) stay as-isAcceptance Criteria
Cascade MCP tools return identical results to current behavior
Reduced code duplication between plugins
New journalism-investigation query capabilities (money_flow, claims) available in Cascade KBs