Improved Scrollable Party- and Contract Ids

[timpel-fcs]

Summary

• Show full party/contract IDs with horizontal scroll instead of ellipsis or abbreviated previews.
• Update CopyableIdentifier / MemberIdentifier with hidden native scrollbar and 4px hover scroll track via shared identifierStyles + useHorizontalScrollMetrics.
• Enhance common PartyId from SV only: partyIdScrollGlobalStyles and PartyIdScrollTracks mounted in Layout.tsx (DSO, validator licenses, config diffs).
• Add optional scrollableIdentifier on TextField, SelectField, and ProposalSummary for long ID form/review fields.
• Add component test to ensure IDs are rendered correctly.

Fixes #1785

Pull Request Checklist

Cluster Testing

• If a cluster test is required, comment /cluster_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.
• If an upgrade test is required, comment /upgrade_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.
• If a hard-migration test is required (from the latest release), comment /hdm_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.
• If a logical synchronizer upgrade test is required (from canton-3.5), comment /lsu_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.

PR Guidelines

• Include any change that might be observable by our partners or affect their deployment in the release notes.
• Specify fixed issues with Fixes #n, and mention issues worked on using #n
• Include a screenshot for frontend-related PRs - see README or use your favorite screenshot tool

Merge Guidelines

• Make the git commit message look sensible when squash-merging on GitHub (most likely: just copy your PR description).

[timpel-fcs]

@pawelperek-da

[pawelperek-da]

Woah, that's cool :)