Tracking: CIP-0104: Scan Reward computations

[adetokunbo]

Implements the scan-based computation of app rewards
Several PRs to add to a feature branch that add a schema, define computations, and add endpoints to the Scan API.

Testing

• A Store test (DbScanAppRewardsStoreTest) updated each PR
  • The store test is introduced in Scan app: Add ScanAppRewardsStore schema migration and CRUD store class #4379 and gets extended in each subsequent PR
• Integration test — ScanAppRewardsComputationIntegrationTest
  • Like the store test, but is introduced with Scan app: Traffic-based App Rewards: compute aggregateActivityTotals; add access via a new endpoint #4380 and only extended in PRs that add Scan API endpoints, testing the full HTTP pipeline via sv1ScanBackend
  • Scan app: Traffic-based App Rewards: trigger off with DAML workflow #4383 adds an integration test that verifies a real computation
• Trigger — RewardComputationTrigger is introduced in PR 2 and extended in subsequent PRs.
  • Initially fires on DB conditions (round closed + no root hash) and has a FIXME for the missing CalculateRewardsV2/ProcessRewardsV2 contract check (Daml not yet on feature branch).
  • Scan app: Traffic-based App Rewards: trigger off with DAML workflow #4383 replaces the FIXME with the real contract gate.

Tasks

• Scan app: Add ScanAppRewardsStore schema migration and CRUD store class #4379
  • Migration SQL + ScanAppRewardsStore CRUD skeleton.
  • Store tests: basic insert/read per table.
• Scan app: Traffic-based App Rewards: compute aggregateActivityTotals; add access via a new endpoint #4380
  • aggregateActivityTotals, FeaturedAppRightProvider trait, RewardComputationTrigger (FIXME: no contract check), earliest-available + activity-totals endpoints.
  • Store tests: single-party aggregation, multi-party GROUP BY with alphabetical seq_nums, non-featured exclusion, empty round handling, idempotency, query methods.
• Scan app: Traffic-based App Rewards: compute reward totals #4381
  • computeRewardTotals (CC conversion + threshold). No new endpoints.
  • Store tests: CC conversion, threshold filtering, summary totals.
• Scan app: Traffic-based App Rewards: compute hashes #4382
  • PostgreSQL CryptoHash function, computeRewardHashes, root-hash + batches/{batchHash} endpoints. Trigger extended to all 3 stages with simulated Open Mining round info
  • Store tests: hash computation, Merkle tree structure, batch retrieval.
• Scan app: Traffic-based App Rewards: trigger off with DAML workflow #4383
  • Replace FIXME with CalculateRewardsV2/ProcessRewardsV2 contract gate. (no longer required)
  • Integration test: validate reward calculation for app activity from a real scenario

Spun-out tasks

• Scan App: Add the number of activity records in the round to GetRewardAccountingActivityTotalsResponse #4645
  • Expose the number of activity events in the round a Scan API endpoint
• Scan App: Add counters for computeRewards/RewardComputationTrigger #4634
  • Add metrics that track values computed by computeAndStoreRewards
• RewardComputationTrigger: Parallei task computation #4570
  • Parallelize reward computation