fix(awareness-service): dedupe deliveries by content hash so envelope updates re-deliver

[coodos]

Description of change

Fixes the delivery dedup collision in awareness-service that silently dropped every MetaEnvelope update after the first ingest.

Delivery was uniquely keyed on (subscriptionId, packetId), and since Packet is upserted on the MetaEnvelope id, every re-ingest of an updated envelope reused the same packetId. IngestService.ingest inserts with .orIgnore(), so the second delivery hit the unique key and was silently discarded — a subscriber received each envelope exactly once, ever.

The MetaEnvelope id (packetId) is intentionally not part of the dedup decision anymore; content is. The fix adds a contentHash column to Delivery and changes the unique key to (subscriptionId, packetId, contentHash):

• Re-ingest of the same payload → same hash → .orIgnore() still dedupes. ✅
• Re-ingest of an updated payload → new hash → no collision → a new delivery is queued. ✅
• Retry / dead-letter flow is untouched.

contentHash = sha256(stableStringify(payload.data)), where stableStringify sorts object keys recursively so key ordering does not affect the hash.

Includes a TypeORM-generated migration (1780404367748-AddDeliveryContentHash). The raw generated ADD ... NOT NULL would fail on a populated deliveries table, so it adds the column nullable → backfills legacy rows with a constant → sets NOT NULL, then swaps the unique constraint.

Issue Number

#984

Type of change

• Fix (a change which fixes an issue)

How the change has been tested

• npm run build (tsc) in services/awareness-service/api passes.
• Ran the migration against a throwaway Postgres 16 with the Init schema applied and a pre-existing delivery row: migration:run succeeds, the legacy row is backfilled (contentHash = ''), the column ends up NOT NULL, and the unique constraint becomes (subscriptionId, packetId, contentHash). migration:revert cleanly drops the column and restores uq_delivery_subscription_packet.
• Traced the issue's repro: first ingest queues 1 delivery; unchanged re-ingest is deduped by .orIgnore(); changed re-ingest produces a new contentHash and queues a new delivery, so the delivery count increments.

Change checklist

• I have ensured that the CI Checks pass locally
• I have removed any unnecessary logic
• My code is well documented
• I have signed my commits
• My code follows the pattern of the application
• I have self reviewed my code

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 1d38c749-c201-4b83-9afa-980df19e243a

📥 Commits

Reviewing files that changed from the base of the PR and between ca96956 and d48c5f7.

📒 Files selected for processing (4)

• services/awareness-service/api/src/database/entities/Delivery.ts
• services/awareness-service/api/src/database/migrations/1780404367748-AddDeliveryContentHash.ts
• services/awareness-service/api/src/services/IngestService.ts
• services/awareness-service/api/src/utils/contentHash.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/delivery-content-hash-dedup-984

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