feat: add tagged red thread connections

src/types.ts

@@ -60,6 +60,9 @@ export interface Connection {
   id: string
   fromEvidenceId: string
   toEvidenceId: string
+  label?: string
+  /** Percentage from slack (0) to taut (100). */
+  tightness?: number
 }
 
 export interface Viewport { x: number; y: number; zoom: number }