Add webhook sender, fix analytics eviction drift, add batch-completed event

[amanosiadnan-cmyk]

closes #2
closes #62
closes #67
closes #182

PR Description

Summary

Implements a reusable webhook sender for POST/JSON delivery with configurable timeouts and graceful failure handling.
Fixes analytics counter drift by adjusting internal counters when old records are evicted from the rolling buffer; adds a regression test.
Adds a contract-side BatchProcessingCompleted event and exposes emit_batch_completed() for off-chain callers to reliably signal batch completion. Adds a unit test validating event emission.
What I changed

Added webhook sender utility
File: webhook-sender.ts
Exposes sendWebhook(url, payload, { timeoutMs, headers }) — POSTs JSON, configurable timeout via AbortController, returns the Response.
Integrated webhook sender into Discord notification flow
File: discord-notification.ts
Replaced the previous local fetch logic with the shared sendWebhook call; preserves timeout/error logging and analytics outcomes.
Fixed analytics aggregator eviction counter drift
File: notification-analytics-aggregator.ts
When rotating/evicting old records due to maxRecords, we now decrement the aggregated counters (successCount, failureCount, retryCount, skippedCount) and adjust totalDurationMs / durationSamples so aggregate counters remain consistent with retained records.
Added regression test to guard against drift
File: notification-analytics-aggregator.test.ts
New test asserts snapshot totals reflect only visible records after eviction (no drift).
Contract: added batch completion event & API
File: events.rs
Added BatchProcessingCompleted event (topics: batch_id, category, priority; data: processed_count).
File: autoshare_logic.rs
Added emit_batch_completed(env, batch_id, processed_count) which publishes BatchProcessingCompleted.
File: lib.rs
Exposed emit_batch_completed() as a public contract method.
File: batch_event_test.rs
Unit test verifying the event is emitted, topics contain the batch_id, and data contains processed_count.
Acceptance criteria mapping

Webhooks are successfully delivered.
Implemented generic sendWebhook() and integrated it into DiscordNotificationService which already handles response OK/failure and deduplication.
Failed requests are logged.
DiscordNotificationService continues to log failures/timeouts; webhook utility raises on abort so the caller logs and records analytics failures.
Timeout configuration is supported.
sendWebhook() accepts timeoutMs; DiscordNotificationService passes configured timeout.
Analytics metrics remain consistent with source records.
Eviction-based counter adjustments ensure no drift between retained records and aggregate counters.
Historical recalculations & regression tests
Snapshot logic unchanged (still computes aggregates from visible records), and added test to prevent future regressions.
Contract: Batch completion events
BatchProcessingCompleted defined and published via emit_batch_completed(); test validates emission and values.
Implementation notes & rationale

Webhook sender:
Small, dependency-free util using Fetch + AbortController to centralize timeout semantics and header handling for any webhook integrations.
Analytics aggregator:
The bug came from evicting records but not decrementing aggregate counters; fixing eviction-side adjustments keeps lifetimeCount semantics (ever seen) while making current aggregates consistent.
Snapshot computation still derives results from visible records — counters kept in sync help other uses and internal metrics (and avoid slow O(N) recomputations in hot paths).
Contract change:
Emitting BatchProcessingCompleted from the contract is provided as a permissionless helper method callable by off-chain processors after successful batches. This avoids coupling batch processing logic into the contract storage/locking and keeps contract surface minimal.
Tests & verification

Added unit tests:
Listener: notification-analytics-aggregator.test.ts (regression for eviction/double-check).
Contract: batch_event_test.rs (event emission shape and data).
NOTE: I could not run tests in this environment:
Listener tests require Node modules; run locally with:

[drips-wave]

@amanosiadnan-cmyk Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits