Upgrade to TypeScript 6

[gabitoesmiapodo]

User story / Problem statement

Currently TypeScript is on 5.9.3 across all TS workspaces; 6.x is available.

Expected outcome

All TypeScript workspaces compile cleanly on TypeScript 6.

Acceptance criteria

• typescript 5.9.3 → 6.x in canton-connect-kit, carpincho-wallet, dapp/e2e, dapp/frontend, wallet-service
• tsc -b passes in every package
• Resolve any removed-flag or stricter-check fallout
• Lint + tests pass

Technical notes

Part of #76. Bump in isolation; new major may remove flags or tighten checks.