feat: add the bare-Canton vesting dApp (vesting-lite)

[fernandomg]

Summary

No related issue. Introduces the vesting dApp on bare Canton ("lite"): a vesting-lite
Daml package, a React 19 frontend that talks to a real ledger through the wallet-service
ledgerApi proxy via explicit disclosure, and a one-command dev stack. Replaces the
stampbook example.

This is the base of a stacked pair — feat/vesting-amulet targets this branch and adds
the Splice/Amulet evolution on top, so its PR diff is exactly the lite→amulet delta.

Note: this branch was cut from an older main; main has since advanced with unrelated
docs/CI work, so it will need a rebase before it can actually merge. The diff here (vs the
merge-base) is scoped to just the vesting changes.

Changes

• Replace the quickstart-tally Daml package with vesting-lite (factory → proposal → contract;
  linear + milestone schedules; minGrantAmount; value-preserving cancel→residual)
• Add the vesting-lite Daml test suite
• Replace the stampbook example with a React 19 / react-router / zustand / Tailwind v4 vesting UI
  (direct-access party picker; explicit-disclosure create; live ACS reads)
• wallet-service listAccounts returns the backend user's ledger CanActAs rights
• One-command dev stack + npm workspace wiring

Acceptance criteria

• Vesting lifecycle works on bare Canton via explicit disclosure
• Frontend, Daml, and wallet-service suites green during development
• dev-stack up boots + bootstraps the demo in one command

Test plan

Automated tests

• Daml: cd dapp/daml/vesting-lite && dpm build then cd ../daml-test && dpm test
• Frontend: cd dapp/frontend && npm test && npm run typecheck && npm run build && npm run lint
• wallet-service: cd canton-barebones/wallet-service && npm test && npm run lint
• Integration driver: PKG=<pkg> node scripts/vesting-lite-driver.mjs

Manual verification

Live browser flow on the bare-Canton stack: party pool from the wallet → create-via-disclosure
→ accept → live vesting → claim until claimable is 0.

Breaking changes

None.

Checklist

• Self-reviewed my own diff
• Tests added or updated
• Docs updated (if applicable)
• No unrelated changes bundled in

Screenshots

None.