Add inbound webhook ingestion for connectors (Stripe first) - #1372

Summary

@helpcodeai First slice of inbound webhook ingestion, as discussed and agreed on in #988: the POST /api/webhooks/:connectorId endpoint with Stripe signature verification, the <prefix>_recent_events builtin tool, the WebhookEvent model, and retention. Scoped to Stripe only, per your note to leave the generic HMAC fallback and other providers for follow-ups.

If anything here is off, or there's a better way to do a part of it, please just say so — happy to fix it right away.

Changes

• WebhookEvent Prisma model + 3 new nullable columns on Connector (webhookEnabled, webhookProvider, webhookSecret); webhookSecret is encrypted with the same helpers as authConfig and never returned by any API or tool response (verified against every connector-serializing path, including the export/import util).
• POST /api/webhooks/:connectorId (webhook-ingest.controller.ts), outside ee/: Stripe-Signature verification (HMAC-SHA256 over timestamp.body, 300s replay tolerance), a body cap below the global 10MB limit checked before the HMAC runs, @Throttle() on the route, and an identical response for an unknown connector id, a disabled hook, and a bad signature.
• main.ts's existing raw-body capture (previously only /api/support/webhook) now also covers /api/webhooks/, since the HMAC needs the exact bytes sent, not a re-serialized body.
• <prefix>_recent_events builtin tool, auto-created the same way the existing GraphQL/Email builtins are. It reads WebhookEvent through a new special case in DynamicMcpTools.executeWithEngine() (same pattern as the existing static/email/odata_* cases), since it's a read of our own storage, never an outbound call. Added the matching read-only special case in tool-annotations.ts too, which has its own independent method-name dispatch and would otherwise have left the tool's readOnlyHint unset.
• Retention: a periodic sweep (shaped like ConnectorAuthStatusService's) plus a per-connector cap enforced on insert. Both configurable via WEBHOOK_EVENT_RETENTION_DAYS (default 7) and WEBHOOK_EVENT_MAX_PER_CONNECTOR (default 500), documented in docs/operations/observability.md.
• Fixed 6 pre-existing spec files whose DynamicMcpTools construction used positional arguments that silently shifted out of alignment once the new required constructor parameter was added; one of them (code-mode.integration.spec.ts) would have changed what it actually tested, not just failed to type-check.

Type

• New feature

Testing

• Added/updated unit tests
• Tested manually (described below)

Commands run from packages/backend unless noted:

• npx tsc --noEmit -p tsconfig.json — 0 errors (confirmed against a clean baseline via git stash -u diff; no new errors introduced).
• npm run lint — 0 errors; 11 pre-existing warnings in unrelated files, unchanged.
• npx jest src/connectors/webhook-signature.util.spec.ts — 9/9 (valid signature, wrong secret, tampered body, stale timestamp, malformed/missing header, non-numeric timestamp, length-mismatch guard, empty secret).
• npx jest src/connectors/webhook-events.service.spec.ts — 9/9 (record + dedupe on redelivery, cap enforcement across connectors, query scoping, retention sweep).
• npx jest src/connectors/webhook-ingest.controller.spec.ts — 10/10 (valid delivery, unknown connector, disabled hook, webhooks-not-enabled, wrong provider, bad signature, missing/oversized body, duplicate delivery, non-JSON body).
• npx jest src/mcp-server/dynamic-mcp-tools.webhook.spec.ts — 3/3, exercising the actual tool-dispatch wiring in DynamicMcpTools.executeTool(), not just the service in isolation.
• npx jest src/mcp-server/tool-annotations.spec.ts — 44/44, including the new read-only case for webhook_recent_events.
• npx jest src/connectors src/mcp-server src/health src/common --maxWorkers=2 — 159/163 suites, 3012/3029 tests passed (4 skipped suites, 17 skipped tests, all pre-existing and unrelated).
• node scripts/generate-llms-txt.mjs --check (repo root) — exit 0.

Manual: ran the real backend against a real Postgres instance, through the actual HTTP API (not direct DB writes) — logged in, created a connector with webhookEnabled/webhookProvider: stripe/webhookSecret via POST /api/connectors and confirmed webhookSecret is absent from the response, confirmed the builtin tool was auto-created, called GET .../tools/:toolId/annotations and confirmed effective.readOnlyHint: true, and sent real Stripe-signed deliveries to POST /api/webhooks/:connectorId — valid (200, stored correctly), bad signature (401), unknown connector (401, identical to bad signature), missing signature (401), wrong method (404), and an exact replay of the same event id (200, no error, confirmed via direct DB query that only one row exists). All dry-run rows were cleaned up afterward.

Checklist

• My code follows the existing code style
• I have tested my changes locally
• I have updated documentation (docs/operations/observability.md, regenerated llms-full.txt)
• All existing tests pass
• This PR has a descriptive title

Related Issues

Relates to #988. No separate issue was filed for this slice: the scope (Stripe-only, this endpoint + this tool) was agreed on directly in the #988 discussion, where it was assigned to me.

Cloud vs self-hosted

Same code path on both; no branch anywhere in this PR checks DEPLOYMENT_MODE. Ingestion, verification, storage, and retention all behave identically.

Known follow-ups (left out of this PR on purpose)

• Other providers (Meta/WhatsApp) and the generic HMAC fallback, each needing their own verification scheme — flagged in Webhook ingestion: register a webhook as an MCP resource #988 as separate work.
• The connector export/import format doesn't yet include the three new webhook columns, so exporting a webhook-enabled connector currently loses that config on re-import. Not a security issue (no secret leak either way — it's an explicit allowlist that simply doesn't name these fields yet), just an incompleteness I noticed while checking that webhookSecret can't leak through that path. Happy to add it here or as a follow-up, whichever you'd prefer.