WS-E.1: run e2e on develop pushes (scheduled runs execute main's tree)

[LukasWodka]

Part of epic tracebloc/backend#1106. Full spec: report §5 (mirrored on the epic; artifact https://claude.ai/code/artifact/b4b6e6a6-4d76-4e46-a668-6f4f0f944344). WS-E.1: scheduled workflows run the default branch (main), 45 commits behind — discovery_e2e_test.go/delete_e2e_test.go/delete-teardown don't exist there; the TokenRequest/offboard e2e have NEVER run on a schedule. Add push: branches: [develop] to e2e.yml (~2 min wall).

[LukasWodka]

Shipped in #301 (merged to develop). Closing as completed — CLI refactor epic backend#1106 cleanup.