fix(insight): replace misleading three-column selector with real money-flow network

[EagleFox31]

The editorial owner correctly flagged the previous explorer as three stacked selection columns with two 20-pixel green dashes rather than an interactive network. This PR rebuilds the existing money-flow component (no new CMS model) into a legible, responsive node-link data story.

• All 10 selectable nodes (2 origins, 4 ways to receive, 4 goals) and 24 candidate connections appear at once. SVG curves span the actual distance between node cards and align to HTML hit targets; 2 active arcs are highlighted (one for receipt, one for use). The edge encoding respects documented / conditional / unknown, with unknown dashed and never implied as working. Thickness represents emphasis, not transaction volume (explicitly stated).
• Stronger editorial hierarchy, route presets, status legend, evidence panel with per-step primary citations, icons, better contrast. Mobile: horizontal scrollable real graph, not collapsed forms; accessible HTML buttons, keyboard focus, textual route explanation; honors reduced motion.
• Uses existing journeyData.ts and named Payload moneyFlow block, no invented fees or crypto corridor. New pure network geometry helper with unit coverage of 24 edges and all 32 selection permutations.
• No article or Gate decision altered. The lab prototype remains clearly marked as unverified / noindex. Changes only the presentation of the previously approved development preview. Relevant Insight — graphiques interactifs intégrés aux articles (paiements, données vérifiées, accessibilité) Trigenys/trigenys-editorial-os#92.

Acceptance: run lint, TypeScript, unit tests; inspect rendered desktop/mobile visual before claiming deployed.