Add Euler graph and matrix discovery views

[saulcapital]

Summary

• replace the basic Explore expansion with an interactive Euler-style graph and all eight matrix modes
• normalize V3 vault data and lazily resolve external/Securitize vaults and oracle metadata through the Euler v2 SDK
• add responsive selection results, expanded viewing, deterministic calculation tests, and Euler Lite attribution

Test plan

• Run pnpm test
• Run pnpm lint
• Run pnpm build
• Verify graph node selection, matrix selection, expanded view, and desktop/mobile layouts locally