feat(portfolio): dividend reinvestment button to compound earnings into more keys (#824)

[meem08]

Summary

Closes #824

Holders with unclaimed dividends previously had no UI to reinvest them. This PR adds a Reinvest action on portfolio holding rows so eligible holders can compound their unclaimed dividend earnings back into more creator keys, directly surfacing and submitting the reinvest_dividend contract call.

Scope / What changed

Data model

• Added unclaimedDividend (XLM) to HeldKeyPosition in src/utils/portfolioValue.utils.ts so holding rows know when a dividend balance is available.

Reinvestment math (src/utils/reinvestDividend.utils.ts)

• estimateReinvest — computes the whole keys a dividend buys at the current key price plus the XLM remainder that can't convert to a whole key.
• hasUnclaimedDividend / xlmToStroops helpers.

UI (src/components/common/PortfolioHoldingRow.tsx, ReinvestDividendDialog.tsx)

• Unclaimed dividend badge shown on holding rows where unclaimedDividend > 0.
• A Reinvest button that opens a confirmation modal displaying: the unclaimed amount, the per-key price, the estimated whole keys, and any XLM remainder.
• On confirm, the dialog submits the reinvestment and closes on success.

Contract call (src/hooks/useWallet.ts → useReinvestDividendMutation)

• Follows the existing useTradeMutation pattern (optimistic cache update, rollback on error, invalidation on settle).
• mutationFn targets the reinvest_dividend contract function with the holding's key_id (= creatorId).
• On success the holding row is optimistically updated (adds the received keys and clears the compounded dividend) and the wallet holdings cache is invalidated.

Toast (src/pages/LandingPage.tsx)

• Shows Reinvested [amount] XLM — received [keys] keys on confirmation.

Tests

• src/utils/__tests__/reinvestDividend.utils.test.ts — estimate/remainder matrix.
• src/components/common/__tests__/PortfolioHoldingRow.reinvest.test.tsx — badge shown only when eligible, button hidden without a handler, modal content, onReinvest called with correct key_id, disabled confirm when no whole key is purchasable.
• src/components/common/__tests__/ReinvestDividendDialog.test.tsx — displayed values and unavailable-estimate state.

Acceptance criteria

• Unclaimed dividend badge shown on eligible rows
• Modal shows correct estimated keys and remainder
• Contract called with correct key_id on confirm
• Success toast shows reinvested amount and keys received
• Holding balance updated after successful reinvestment

Verification

• tsc -b passes
• eslint passes on all changed files
• New + affected existing unit tests pass (20 tests)

Notes

Real on-chain calls in this repository are currently simulated (see the existing useTradeMutation comment); useReinvestDividendMutation wires the key_id payload and follows the same shape so the actual reinvest_dividend contract call can be dropped in once ABIs/TypeChain bindings land. This follows the established pattern and keeps the change minimal.

[drips-wave]

@meem08 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