feat(tap-aggregator): add v2 endpoint

[suchapalaver]

Summary

This PR introduces the aggregate_receipts_v2 JSON-RPC endpoint, enabling collection-based receipt aggregation for the Horizon protocol. It maintains full backward compatibility with existing V1 endpoints while supporting a new V2 receipt structure.

---

What’s New

✨ V2 Aggregation Endpoint

• New JSON-RPC Method: aggregate_receipts_v2
• Updated Receipt Format:
  • collection_id (replaces allocation_id)
  • payer, data_service, service_provider (new fields)
• Feature-Flagged: Controlled by the v2 feature flag (enabled by default)

---

Architecture Improvements

• Protocol Mode: Introduces ProtocolMode enum (Legacy vs Horizon)
• Receipt Classification: Centralized validation and protocol detection logic in receipt_classifier.rs
• Structured Validation:
  • Validates collection_id, payer, data_service, service_provider
• Error Handling: V2-specific errors surfaced with meaningful messages

---

Compatibility & Migration

• ✅ V1 endpoints and gRPC support remain unchanged
• 🔁 V2 support can be toggled off via --no-default-features
• 🧭 Phased migration path:
  1. Deploy with V2 enabled
  2. Clients can begin testing V2
  3. Gradual migration to V2
  4. V1 retained for legacy support

---

Signed off by Joseph Livesey [email protected]

[github-actions]

Pull Request Test Coverage Report for Build 16354415176

Details

• 71 of 142 (50.0%) changed or added relevant lines in 2 files are covered.
• 10 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-2.7%) to 73.473%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
tap_aggregator/src/server.rs	26	97	26.8%

Files with Coverage Reduction	New Missed Lines	%
tap_aggregator/src/aggregator/v1.rs	1	93.55%
tap_aggregator/src/server.rs	9	64.85%

Totals
Change from base Build 15931262360:	-2.7%
Covered Lines:	1371
Relevant Lines:	1866

---

💛 - Coveralls

[suchapalaver]

Make sure before deleting branch we update testing infra in indexer-rs that currently uses this branch!