feat: Soroban event parser with decoded arguments and topic filtering

[dotunv]

Overview

Add a Soroban event parser that decodes emitted contract events into human-readable, typed output, including argument decoding and topic filtering.

Motivation

The Transaction Inspector decodes Soroban contract operations but does not decode the events emitted during execution. Events carry crucial state-change signals (e.g., a mint or a transfer). Developers need to decode these events to understand what a contract actually did, rather than reading raw XDR.

Proposed Design

1. Add a decoder that parses Soroban event topics and data into typed values (Bool, I32, U64, I128, U128, Bytes, String, ContractId, Vec, Map, Address)
2. Extract events from a transaction's result and render them with a readable contract/event signature
3. Surface events in the Transaction Inspector result view, grouped by contract
4. Add topic-based filtering (e.g., filter by contract ID or event name)
5. Support resolving well-known event topics to friendly names via a small mapping
6. Handle unknown/unresolvable topics gracefully by showing raw hex
7. Provide a GET /api/inspector/:txHash/events endpoint returning decoded events as JSON

Acceptance Criteria

• Soroban events are decoded from transaction results
• Common scalar and container types are decoded correctly (incl. nested Vec/Map)
• Events are rendered grouped by emitting contract
• Users can filter events by contract ID or event name
• Well-known topics map to friendly names; unknown topics fall back to raw hex
• GET /api/inspector/:txHash/events returns decoded JSON events
• Malformed event data does not crash the inspector (graceful fallback to raw)
• Tests cover: scalar decode, container decode, unknown topic fallback, filter, API response

[ojuotimi932]

@ojuotimi932 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi Maintainer Can I resolve this kindly assign

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[Demilade10]

@Demilade10 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi I can fix this

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[Obaara293]

@Obaara293 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, I've reviewed the issue and I've recognized the solution, kindly assign this to me to get the best result.

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[Maxwell-tom]

@Maxwell-tom has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, Can I work on this?

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[zillaXBT]

@zillaXBT has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

After reviewing the issue, I believe I have the skills needed to address it properly. I’d be glad to take ownership of the task.

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