No transaction wrapping event writes + cursor update

[DeFiVC]

What

Events are dispatched and the cursor is updated via separate, independent DB operations with no wrapping transaction. If the process crashes after dispatchEvent(eventN) but before cursor.flush(), the cursor is not updated in the database.

Why

On restart, the indexer re-fetches and re-processes all events since the last flush — potentially hundreds of events. While the upserts are idempotent (no data corruption), this wastes significant time and DB resources.

Scope

• Wrap event writes and cursor update in a single transaction
• Or accept the re-processing and document it

Acceptance Criteria

• Event writes and cursor update are atomic
• No re-processing window on crash

Technical Context

• File: src/indexer/event-listener.ts, lines 108-113

[fathiaoyinloye]

Hi, I'd like to work on this issue. I have relevant experience with the technologies and concepts involved, and I'm confident I can make the necessary implementation to ensure the it meets the acceptance criteria. I'd be happy to contribute to this task.