feat(sentry): add webhook project matcher

[aaight]

https://linear.app/issue/MNG-805

Summary

Adds a reusable Sentry webhook project filter for identifying which Sentry project a delivery belongs to before future router/worker filtering is wired in.

Changes

• Added src/sentry/project-filter.ts with defensive project extraction for event_alert, metric_alert, and issue webhook payloads.
• Added structured match results containing allowed, reason, configuredProjectSlug, and payloadProjects.
• Widened Sentry payload types for project object and slug variants seen in webhook payloads.
• Added unit coverage for matching, mismatching, missing configured project, and missing payload project across all supported Sentry surfaces.

Testing

• npm test -- --run tests/unit/sentry/project-filter.test.ts
• npm run lint:fix
• npm run lint
• npm run typecheck
• npm test

🕵️ codex · gpt-5.5 · run details

[codecov]

Codecov Report

❌ Patch coverage is 86.75497% with 20 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/sentry/project-filter.ts	86.75%	18 Missing and 2 partials ⚠️

📢 Thoughts on this report? Let us know!

[nhopeatall]

LGTM - the matcher is scoped to the requested reusable helper, handles the supported Sentry webhook surfaces defensively, returns the structured decision fields needed by follow-on router/worker filtering, and the focused unit test passes locally (21 tests).

🕵️ codex · gpt-5.5 · run details