feat(transactions): virtualize list and add cursor-based pagination - #665

…nChippay#384)

- Add PaymentBuilder component with drag-and-drop recipient reordering and drop targets
- Add QuickAddPanel for dragging token types (XLM, USDC) and preset amounts
- Add BatchSummary component with distribution bar chart and fee estimation
- Integrate payment builder mode toggle into SendPaymentForm and BatchPaymentForm
- Add undo/redo state history with shortcuts (Ctrl+Z / Ctrl+Shift+Z / Ctrl+Y)
- Implement screen reader live announcements for all payment builder actions
- Add comprehensive unit test suites and Storybook stories

The 'Manual Greptile Review' job was skipped on every PR because it was
gated to workflow_dispatch only, and the 'label-pr' job failed on fork
PRs (read-only GITHUB_TOKEN) so it was disabled. Move labeling to a
pull_request_target workflow that works for forks (API-only, never
executes PR code) and let the manual-review job validate the Greptile
config as a PR status check.

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Co-Authored-By: Codebuff <noreply@codebuff.com>

…ken safety

The contract caches its own token balance (LastContractBalance) to avoid
re-reading token.balance(contract) on every deposit. For standard assets the
cache matches reality, but a rebasing or fee-on-transfer token (or any token
whose transfer moves less than the requested amount) can desynchronise the
cache from the real on-chain balance. A drifted cache could weaken the
phantom-deposit check in require_transfer_succeeded and let locked-balance
accounting over-claim.

Changes:
- Harden require_transfer_succeeded: the "before" balance for the
  phantom-deposit check is now the actual on-chain balance (via
  get_contract_balance), never a possibly-stale cache, so a fee-on-transfer
  deposit can never pass the check and over-claim.
- get_contract_balance now detects drift on read: when the cached value
  differs from token.balance(contract) it emits a balance_drift_detected
  event with (cached, actual) and self-heals the cache.
- Add admin-gated reconcile_balance (via propose_admin_action action_type
  "reconcile_balance") that resyncs LastContractBalance with the actual
  balance and emits a balance_reconciled event with (old, new).
- Add tests/balance_reconciliation.rs with FeeOnTransferToken (99% fee) and
  RebasingToken mocks proving deposits/claims stay correct across escrow,
  stream, and multi-sig flows and that no funds can be over-claimed.
- Document the supported token model (standard non-rebasing assets) and the
  failure mode for fee-on-transfer / rebasing tokens.
- Bump CONTRACT_VERSION to 4.

🤖 Generated with Codebuff
Co-Authored-By: Codebuff <noreply@codebuff.com>

Resolve conflicts in frontend/.eslintrc.json, frontend/lib/api.ts, and
frontend/__tests__/PaymentBuilder.test.tsx:

- eslintrc: keep both the next.rootDir setting and upstream's disabled
  no-html-link-for-pages rule
- api.ts: adopt upstream's correlation-ID tracing for the fetch wrapper
  while keeping the cursor-pagination primitives
- PaymentBuilder.test.tsx: keep the CodeQL-fixed (act-removed) version