feat(sdk): add bulk replay to api and sdk (#4105)

## Summary

Adds SDK and API support for run bulk actions. You can now create bulk
cancel or replay actions from `@trigger.dev/sdk` using run IDs or the
same filters as `runs.list()`, then retrieve, list, poll, or abort the
action by its `bulk_` handle.

Tests, docs, changesets added.

## Design

The dashboard bulk action service now accepts structured filters instead
of reading directly from a dashboard request, so the dashboard and API
share the same creation path. Replay actions created through the API are
attributed with the existing `api` trigger source, while
dashboard-created actions keep `dashboard`.

The SDK exposes the new surface under `runs.bulk.*`, including
`targetRegion` for replay region overrides and cursor pagination for
listing bulk actions.

## Filters and runIds

Nuance on filters. If `filter` is provided, it MUST have at least one
key. This is to remove the footgun of passing no filter and selecting
all runs.

```typescript
   { action: "cancel", runIds: ["run_1"] } // valid
   { action: "cancel", runIds: [] } // invalid, min(1)
   { action: "cancel", filter: { status: "FAILED" } } // valid
   { action: "cancel", filter: {} } // invalid
   { action: "cancel", filter: {}, runIds: ["run_1"] } // invalid
```

.server-changes/bulk-actions-api-sdk.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: feature
+---
+
+Add API and SDK support for creating, listing, retrieving, polling, and aborting run bulk actions.