Integrate indexed event idempotency into poller dispatch

[pragmaticAweds]

Context

EventRepository can record deterministic event identity, and the guidelines require idempotent processing. The current poller and handler registry process events but do not yet skip already-recorded events or record successful processing as part of dispatch.

Scope

• Define how SorobanEventInput maps to indexed event identity fields
• Add a poller or dispatcher integration point for EventRepository
• Skip events that are already recorded as processed
• Record event identity only after all matching handlers succeed
• Ensure failed or retriable handler results do not advance idempotency state
• Add tests for duplicate events, successful processing, handler failure, and no-handler events

Out of Scope

• Creating the indexed events table
• Building domain-specific repositories
• Changing Soroban contract event formats

Acceptance Criteria

• Reprocessing the same event does not call domain handlers twice
• Failed handler dispatch leaves the event unrecorded for retry
• Event identity includes contract ID, ledger number, transaction hash or paging token, and deterministic event index when available
• Behavior is covered by unit tests with mocked repositories and handlers
• bun run indexer:type-check passes
• bun run indexer:test passes
• bun run indexer:lint passes

Dependencies

• Create indexed events idempotency table #25
• Implement indexed event repository #27
• Implement event polling loop #29

Suggested Files or Packages

• indexer/common/src/poller/
• indexer/common/src/handlers/
• indexer/common/src/db/repository.ts

[Abba073]

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[Emelie-Dev]

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[6akola]

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Please, I would love to work on this issue.
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[Okorie2000-code]

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Hi maintainer, can i work on this ? i can submit a clean PR before the deadline.

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[GreatShinro]

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Hi, can I work on this please?

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[intelliDean]

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