fix: show exact deadline status from ledger time

[Sabira2003]

Summary

Updates dispute deadline handling so staking and voting status is determined from authoritative Stellar ledger close time instead of the user's local browser clock.

Changes

• Added a server-side endpoint for retrieving the latest Stellar ledger close time
• Added deterministic ledger-time state handling
• Updated staking deadline checks to use ledger time
• Updated voting deadline checks to use ledger time
• Updated countdown display to support authoritative ledger time
• Preserved existing CountdownTimer callers through an optional currentTime prop
• Preserved the last successful ledger snapshot when refreshes fail
• Added loading, stale, error, permission and retry handling
• Disabled deadline-sensitive actions when authoritative ledger time cannot be safely verified
• Prevented older/out-of-order responses from replacing newer ledger state
• Added focused deadline boundary and regression coverage

Deadline invariants

• Browser wall-clock time does not determine staking or voting deadline status
• Exact equality between ledger time and a deadline is treated as expired
• One second before the ledger deadline remains open
• Stale or unavailable ledger state cannot enable a deadline-sensitive action
• Older ledger responses cannot overwrite a newer ledger snapshot
• Existing dispute data interfaces remain unchanged

Validation

Focused deadline tests:

• 24 tests passed
• Ledger time overrides incorrect browser time
• Exact deadline equality is handled deterministically
• One-second-before-deadline boundary remains open
• Missing ledger time shows a loading state
• Existing countdown behaviour remains covered
• Expired and invalid deadline handling remains covered
• Accessibility and reduced-motion behaviour remain covered

Command:

pnpm exec jest components/disputes/shared/__tests__/CountdownTimer.test.tsx --runInBand

Result:

Test Suites: 1 passed, 1 total
Tests: 24 passed, 24 total

Repository-wide pnpm type-check was also attempted. It is currently blocked by pre-existing syntax errors in unrelated files including CopyAddress.tsx, WalletBalance.tsx, WalletMenu.tsx, QuickBetPresets.tsx, Receipt.tsx, and notifications.test.ts. None of those files are modified by this PR.

No new dependencies were added.

Closes #890

[vercel]

@Hakimziyech18 is attempting to deploy a commit to the Jagadeesh B's projects Team on Vercel.

A member of the Team first needs to authorize it.

[drips-wave]

@Sabira2003 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits