Rename "Validator faucet cap" UI label to "Validator liveness reward cap"

[samsondav]

Summary

Aligns user-facing terminology with the Canton Coin whitepaper, which uses "liveness rewards" rather than "faucet" for the per-round validator rewards. Fixes #958.

• apps/sv/frontend: relabel the two optValidatorFaucetCap rows in the SV governance minting curve diff view ("Validator faucet cap" -> "Validator liveness reward cap").

Scope

Per the original issue author's guidance ("No changes to Daml code; just UI for now"), this is intentionally minimal:

• No Daml changes. The final diff leaves splice-amulet untouched to avoid triggering a Daml package/version change.
• No on-chain ABI changes. The ValidatorLivenessActivityRecord template already exists alongside the deprecated ValidatorFaucetCoupon; the wallet OpenAPI already exposes both endpoint sets. Renaming FaucetState, optValidatorFaucetCap, optIssuancePerValidatorFaucetCoupon, etc. would break on-chain contract compatibility for fields still in active templates and is out of scope.
• No public API renames. The Scan OpenAPI endpoints (/v0/validators/validator-faucets, /v0/top-validators-by-validator-faucets) are unchanged here. Adding a parallel "liveness" set (mirroring what was done for the wallet API) would be a reasonable follow-up but is a separate concern from a label rename.
• No internal Scala/test renames. Many internal classes (e.g. ReceiveFaucetCouponTrigger, listValidatorFaucetCouponsOnDomain) still process the deprecated ValidatorFaucetCoupon template -- their names accurately describe what they do. They can be revisited if/when the deprecated template is removed.

Test plan

• git diff --check
• npm run format:check --workspace @lfdecentralizedtrust/splice-sv-frontend from apps
• Reviewed the final PR diff: it is now limited to the two user-facing SV frontend label strings.

[samsondav]

Addressed the review comments: removed the Daml docstring change, removed the added label-only unit test, and updated the PR body/test plan. The final diff is still limited to the two SV frontend label strings.

The first CI run had one wall-clock-time shard fail after its tests passed, during checkErrors log scanning (log/canton_network_test.clog contains problems) with transient TopupMemberTrafficTrigger missing-wallet warnings. I cannot rerun failed jobs directly (Must have admin rights to Repository), so I pushed empty commit de30562c0 to trigger a clean rerun without changing the diff.

@isegall-da the PR is approved, mergeable, and the rerun is blocked only on fork-CI approval:

• Workflow: CI on PRs from forks (.github/workflows/pr_non_contributors.yml)
• Run: https://github.com/canton-network/splice/actions/runs/25563933558
• Job: Approve CI for Forks https://github.com/canton-network/splice/actions/runs/25563933558/job/75042376708
• Environment: ci-forks
• Required environment reviewers: splice-maintainers or splice-admins

GitHub reports that my account cannot approve this environment gate, so someone in one of those maintainer/admin teams needs to approve it to let the clean rerun proceed.

[isegall-da]

Thanks