feat(sentry): convert breadcrumbs to Hawk format

[MrFallen]

What

Sentry events now carry their breadcrumbs into Hawk's native payload.breadcrumbs field, so they are rendered by the Breadcrumbs block in Garage like the ones from @hawk.so/javascript.

Breadcrumbs were removed from the Sentry worker in #406 because they landed in addons as raw JSON, with the note that Hawk should support them first. Hawk now does: EventData.breadcrumbs exists in @hawk.so/types, Garage renders it, and the grouper already sanitizes message and data of every breadcrumb. This PR does not bring back the raw addon: breadcrumbs are still excluded from addons.sentry.

How

composeBreadcrumbs() in workers/sentry/src/utils/converter.ts:

• reads both shapes SDKs send: a plain array (JavaScript) and { values: [...] } (Python, PHP);
• converts the timestamp to Unix milliseconds: Sentry sends Unix seconds with a fraction or an RFC 3339 string. A breadcrumb without its own timestamp gets the event timestamp; if there is none either, the breadcrumb is skipped, because Breadcrumb.timestamp is required;
• maps Sentry breadcrumb types to the ones Garage knows: http/query → request, ui/user → ui, transaction → logic, debug/info → default; navigation, error and default stay as they are, unknown types pass through unchanged (Garage shows them as default);
• keeps category, message, level and object data as they are.

The number of breadcrumbs is left to the SDK (max_breadcrumbs, 100 by default in Sentry SDKs); the worker does not truncate them.

Tests

• converter.test.ts: array and { values } shapes, seconds and RFC 3339 timestamps, fallback to the event timestamp, skipping without a timestamp, type mapping, unknown types, missing breadcrumbs.
• index.test.ts: an envelope with a PHP/Python-style { values } payload ends up in payload.breadcrumbs and not in addons.sentry.

yarn test:sentry: 50 passed.