Add support for Polymesh Confidential Assets events

[F-OBrien]

Description

What changed

schema.graphql — Removed the 9 v1 entities (ConfidentialVenue, ConfidentialTransaction, ConfidentialAssetHolder, ConfidentialAssetHistory, ConfidentialAssetMovement, etc.) plus their confidential-only enums/jsonFields. Kept AffirmStatusEnum (used by regular settlements) and reused AffirmingPartyEnum. Added 8 new entities:

ConfidentialSettlement — id is the settlement ref (hash of the creation proof), with memo, assetRootBlock, legCount, and status (Pending/Executed/Rejected/Finalized)
ConfidentialLeg — stores each leg's SCALE-encoded encrypted data as hex. This is the critical piece: settlement.rs::finalize() deletes legs, memo, and all affirmation statuses from chain storage, so the indexer is a durable record
ConfidentialLegAffirmation — latest per-party per-leg status; mediators keyed by key index
ConfidentialCurveTreeLeaf — leaves of the Asset/Account/FeeAccount curve trees (needed to rebuild trees for proof generation; asset-tree leaves update in place, the others are append-only)
ConfidentialAccount, ConfidentialEncryptionKey, ConfidentialAsset (name/symbol/decimals/data, mediator key pairs, auditor keys, totalSupply), ConfidentialAccountAsset

Mappings — the four files in src/mappings/entities/confidentialAssets/ were replaced with mapConfidentialAccount, mapConfidentialAsset, mapConfidentialSettlement, and mapConfidentialCurveTree. One handler covers all eight leg-affirmation events, mapping them to party + status (e.g. SenderCounterUpdated/ReceiverClaimed → Finalized, *AffirmationReverted → Reverted), which also converges correctly for the instant-settlement flow that emits Affirmed followed by the finalizing event.

project.ts — the old confidentialAsset module keeps only generic event indexing (it never ran on a production chain); all new-pallet events are wired, with fee-account POLYX movements, relayer batches, and curve-tree root events intentionally left to the generic events table (roots expire by design and are derivable from leaves).

No DB migration needed — subql-node v6 auto-creates/drops entity tables and enum types on schema upgrade, and the new event/call enum values were already added in migration 14.

Verification

25 new unit tests in tests/unit/confidentialAssetHandlers.test.ts covering every handler including update paths and error cases — full unit suite passes (126 tests, 7 suites)
yarn build and yarn lint both clean; tsc --noEmit shows only a pre-existing @types/rimraf issue that exists on the clean tree too

Breaking Changes

JIRA Link

Checklist

• Updated the Readme.md (if required) ?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud