* test: add a manually dispatched integration trial on larger runners
Runs the providers, database and management integration groups on 16-core GitHub-hosted runners with Postgres and Redis as service containers, to measure wall time and how far each group scales with more workers
run_integration.sh now keeps a preset INTEGRATION_WORKERS, takes the service container names from the environment, and seeds test order from the GitHub run when there is no CircleCI one
* test: run the integration trial on push to this branch
* test: give integration trial workers a local redis-server
* test: run the providers trial on a 64-core runner with 32 workers
The 16-core run reached 53% of providers in 45 minutes with 16 workers, which points at CPU. Postgres gets max_connections=1000 and a 1 GB shm because one server now backs 32 worker proxies, where each CircleCI machine backs 4
* test: run every integration group in the trial on sized runners
* test: add a scan that refuses to upload integration results holding the license
* test: drop the member-name pass the archive byte scan already covers
* test: use a secret whose base64 and base64url encodings differ
* ci: run integration groups on run-ci pull requests and scheduled main runs
* ci: scope the integration license to a protected environment
Backport note: tests/integration/AGENTS.md keeps rc/1.108.0's text, since main's copy of that paragraph also carries later changes rc does not have
(cherry picked from commit 62b8ee78de)
