List and filter Browserbase sessions by status and user metadata via the REST API

Documented steps

1. Authenticate with the header X-BB-API-Key: <api-key>. Reference: https://docs.browserbase.com/reference/api/list-all-sessions
2. GET https://api.browserbase.com/v1/sessions. The response body is a JSON array of Session objects (not an envelope object).
3. Filter by lifecycle state with the query parameter status, using one of the case-sensitive enum values RUNNING, ERROR, TIMED_OUT or COMPLETED.
4. Filter by metadata you attached at creation with the q query parameter, which queries the session's userMetadata object.
5. Attach userMetadata at session-creation time (POST /v1/sessions) so that later q-based lookups can find the session - there is no way to tag a session retroactively for this purpose.
6. Read per-session fields from each element: id, createdAt, updatedAt, projectId, status, startedAt, endedAt, expiresAt, proxyBytes, keepAlive, contextId, region, userMetadata.
7. To watch a specific session, poll GET /v1/sessions?status=RUNNING and match on id, since the docs do not publish a single-session GET endpoint - do not assume GET /v1/sessions/{id} exists.
8. Use proxyBytes from the listing to track proxy data consumption, which is what Browserbase bills proxy usage on.