fix(#50): add transaction history tracking

[senmalong]

Summary

Closes #50

Implements full transaction history tracking — store, types, screen with detail view, and block explorer links.

Files

src/types/transaction.ts (new)

• Transaction interface: id, subscriptionId, subscriptionName, amount, currency, status, type, date (ISO), txHash, chainId, explorerUrl, failureReason, notes
• TransactionStatus enum: pending | confirmed | failed | cancelled
• TransactionType enum: fiat | crypto | refund

src/store/transactionStore.ts (new)

• Zustand store persisted to AsyncStorage (subtrackr-transaction-history)
• addTransaction — prepends and caps at 500 records
• updateTransactionStatus — update status + optional failure reason
• getBySubscription / getByStatus — filtered selectors
• clearHistory

src/screens/TransactionHistoryScreen.tsx (new)

• FlatList of all transactions, newest first
• Filter chips: All / Confirmed / Pending / Failed
• Each row: subscription name, date, type, amount, colour-coded status badge; crypto rows show shortened tx hash
• Tap a row → bottom-sheet detail panel with full fields
• Block explorer link: Linking.openURL(explorerUrl/tx/txHash)

src/store/index.ts — exports useTransactionStore

src/navigation/types.ts — adds TransactionHistory route

src/navigation/AppNavigator.tsx — registers TransactionHistoryScreen

Acceptance Criteria

• Transactions stored (Zustand + AsyncStorage, capped at 500)
• History screen displays transactions with filter chips
• Details show amount, date, status, tx hash, chain ID, failure reason
• Links to block explorer work via Linking.openURL

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[Smartdevs17]

⚠️ Merge failed — check CI status.

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[Smartdevs17]

❌ This PR has merge conflicts.

Hi @senmalong,

Please resolve the conflicts with main so this can be merged.

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[senmalong]

@Smartdevs17 conflict resolved

[senmalong]

@Smartdevs17 kindky review

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